[No ticket] Upgrade to database_cleaner 2

The library is now splitted into multiple gems, depending on the ORM / database you use.

Changes since 1.7.0:

```
== 2.0.1 2021-02-04

== Bugfixes
  * Regression: allow_remote_database_url and url_allowlist not working anymore: DatabaseCleaner/database_cleaner#671

== 2.0.0 2021-01-31

=== Changes
  * Rename `url_whitelist` to `url_allowlist`
  * Allowlist now supports regular expressions
  * Fixed Ruby 2.7 deprecation warnings

=== Breaking changes
  * Failed checks against the allowlist now raise `UrlNotAllowed` rather than `NotWhitelistedUrl`

== 2.0.0.beta2 2020-05-30

=== Features
  * New API for ORM Adapter gems: DatabaseCleaner/database_cleaner#644

=== Breaking changes
  * Rename :connection configuration option to :db for consistency: DatabaseCleaner/database_cleaner#650
  * Remove all #orm= setter methods: https://github.com/DatabaseCleaner/database_cleaner/pull/643/files
  * drop support for Ruby 2.4 which is EOL as of 2020-03-31: DatabaseCleaner/database_cleaner#635

== 2.0.0.beta 2020-04-05

=== Breaking changes
  * Replace old shared RSpec examples with new "database_cleaner adapter" example: DatabaseCleaner/database_cleaner#629
  * split gem into database_cleaner-core and database_cleaner metagem.
  * Support Ruby versions 2.4, 2.5, 2.6, and 2.7, and drop support for older Rubies.
  * remove all deprecated code and get the specs passing again.
  * Split off all adapter gems into their own repos: DatabaseCleaner/database_cleaner#620

== 1.99.0 2021-01-31

== Changes
  * Remove unnecessary dependency on database_cleaner-mongo from database_cleaner-mongoid: @botandrose
  * Enable the :cache_tables option for the mongo truncation strategy, and default to true: DatabaseCleaner/database_cleaner#646"
  * Introduce deletion aliases for truncation strategies for mongo, mongoid, and redis adapters. DatabaseCleaner/database_cleaner#654
  * Add new :db orm configuration key, for consistency with #db and #db=. DatabaseCleaner/database_cleaner#649

== Deprecations
  * Deprecate all #orm= setter methods: DatabaseCleaner/database_cleaner#643
  * Deprecate non-functional :reset_ids option in ActiveRecord truncation strategy: DatabaseCleaner/database_cleaner#559
  * Deprecate mongo truncation's `:cache_tables => true` option in favor of `false`, to prep for caching removal in v2.0: DatabaseCleaner/database_cleaner#646"
  * Deprecate redis truncation's #url method in favor of #db: @botandrose
  * Deprecate mongo, mongoid, and redis truncation strategies in favor of deletion. DatabaseCleaner/database_cleaner#654
  * Deprecate :connection and :model configuration options in favor of :db for consistency: DatabaseCleaner/database_cleaner#650

== Bugfixes
  * Fix deprecation warning about `DatabaseCleaner.connections` to recommend a better alternative: DatabaseCleaner/database_cleaner#656

== 1.8.5 2020-05-04

=== Bug Fixes
  * Fix :mongo strategy: DatabaseCleaner/database_cleaner#645

== 1.8.4 2020-04-02

=== Bug Fixes
  * Fix false positive deprecation warnings on Windows: DatabaseCleaner/database_cleaner#633

== 1.8.3 2020-02-18

=== Bug Fixes
  * Fix performance issue of DatabaseCleaner::Base#orm_module: DatabaseCleaner/database_cleaner#625

== 1.8.2 2020-02-01

=== Bug Fixes
  * Fix database_cleaner-ohm autodetected adapter loading: DatabaseCleaner/database_cleaner#619
  * Fix database_cleaner-mongo_mapper autodetected adapter loading: @botandrose
  * Fix database_cleaner-mongoid autodetected adapter loading: DatabaseCleaner/database_cleaner#617
  * Exclude ar_internal_metadata from truncation on Rails 5: DatabaseCleaner/database_cleaner#588

=== Changes
  * Deprecate ohm adapter: DatabaseCleaner/database_cleaner#619

== 1.8.1 2020-01-30

=== Bug Fixes
  * Remove undeclared active_support dependency: DatabaseCleaner/database_cleaner#612

== 1.8.0 2020-01-29

=== Bug Fixes
  * Fix MySQL deprecation warnings with Rails 5: DatabaseCleaner/database_cleaner#574
  * Fix MySQL truncation with `pre_count: true`: DatabaseCleaner/database_cleaner#498
  * Fix primary key sequence resetting in Sequel with Postgres and SQLite: https://github.com/DatabaseCleaner/database_cleaner/pull/538/files
  * ActiveRecord truncation adapter doesn't work with Oracle: DatabaseCleaner/database_cleaner#542

=== Changes
  * Extract ORM adapters into gems: DatabaseCleaner/database_cleaner#560
  * Allow postgres:///dbname as a local url: DatabaseCleaner/database_cleaner#569
  * Add an optional URL whitelist safeguard: DatabaseCleaner/database_cleaner#526
  * Add `local` tld to safeguard check: DatabaseCleaner/database_cleaner#547
  * Speed up ActiveRecord deletion strategy: DatabaseCleaner/database_cleaner#534
  * Consider `sqlite:` database urls to be local: DatabaseCleaner/database_cleaner#529
```

back/Gemfile

@@ -33,7 +33,7 @@ group :development, :test do
   gem 'pry-byebug'
   gem 'pry-rails'
   gem 'pry-stack_explorer'
-  gem 'database_cleaner'
+  gem 'database_cleaner-active_record'
   gem 'factory_bot_rails'
   gem 'license_finder'
   # Use module prepend to patch NET::HTTP to avoid stack level too deep errors.

back/Gemfile.lock

@@ -571,7 +571,10 @@ GEM
     css_parser (1.7.0)
       addressable
     dalli (2.7.9)
-    database_cleaner (1.7.0)
+    database_cleaner-active_record (2.0.1)
+      activerecord (>= 5.a)
+      database_cleaner-core (~> 2.0.0)
+    database_cleaner-core (2.0.1)
     debug_inspector (1.0.0)
     declarative (0.0.20)
     diff-lcs (1.4.4)
@@ -1132,7 +1135,7 @@ DEPENDENCIES
   custom_style!
   custom_topics!
   dalli
-  database_cleaner
+  database_cleaner-active_record
   email_campaigns!
   factory_bot_rails
   faker