Release/1.21 (#1059) (#1060)

* Task/submission review assignments (#1046)

* WIP: misc formatting, typos, cleanup

* WIP: add modal to layout

* WIP: add modal controller

* WIP: add assign review modal

* WIP: Use modal on grant submissions index

* WIP: remove policy scope from submissions controller

* WIP: add submission.eligible_reviewers specs

* WIP: update submission index specs

* WIP: display explanation when reviewer/review limits reached

* WIP: resolve merge conflict

* WIP: additional modal close options

* Redirect opt-out reviewer to grant, update specs (#1047)

* Move modal frame to a partial (#1048)

* Update jquery-ui-rails gem (#1049)

* Task/rework reviewer assignment page (#1053)

* Redesign reviewer tab and review assignment process

* Add assignment of reviews to the Submission page

* Task/update manage links (#1055)

* Update manage grant links

* Add specs for panel and permissions links

* WIP: remove condition for edit link display

* Task/fix grant redirect on slug change (#1056)

* Reload grant on edit to get current friendly url

* WIP: add friendly url spec, remove instance variables

* WIP: rubocop refactor, code and comment cleanup

* WIP: add draft banner specs

* Task/misc updates (#1057)

* WIP: removed unused scope

* WIP: delete unused partial

* WIP: Clarify tool tip text for score count and scores

* WIP: Remove unused css file

* WIP: prevent page bouncing on clear file button click

* WIP: remove file clear button after click

* Reduce n+1 queries on panel page

* Bump rails, hotwire

* Add stimulus controller to Remove disallowed characters from slug input

* Hide assign review on Submission index after review period

* Code cleanup

* Bump version, update release notes