feat: known EVM networks & tokens (#67)

* wip: collect known evm networks & tokens data

* feat: logos download steps

* feat: partial provisioning of logos

* wip: partial logo provisioning

* wip: partial token logos provisioning

* wip: partial token logos provisioning

* feat: logos provisioning

* feat: logos provisioning completed

* wip: evm native token overrides

* fix: disable steps temporarily

* chore: logo provisioning update

* wip: rework build

* fix: fetch external

* fix: evm-networks schema compliance

* fix: substrate tokens coingecko logos provisioning

* feat: chains extra cache

* fix: token logos

* fix: substrate native token logos

* fix: chaindata schema

* feat: file structure section in readme

* fix: token cache duplicates

* wip: polishing

.env.sample

@@ -2,3 +2,6 @@
 # Only needed when running `bun run build` locally
 # When it's run on the CI, GitHub automatically generates a GITHUB_TOKEN for the job
 GITHUB_TOKEN=
+
+# Should only be necessary when running on the CI
+COINGECKO_API_KEY=

README.md

@@ -62,3 +62,21 @@ To make a contribution, please fork this repo and make your changes in your fork
 1. Copy `.env.sample` to `.env` and fill in the variables
 1. Run the build via  
    `pnpm build`
+
+### File structure
+
+Some files are edited manually, some other are generated automatically as part of the CI.
+
+The table below describes the purpose of each file and how it is edited.
+
+| File name                             | Edit Type | Purpose                                                                                       |
+| ------------------------------------- | --------- | --------------------------------------------------------------------------------------------- |
+| `chaindata.json`                      | manual    | A list of all parachains and relay chains in the Polkadot ecosystem                           |
+| `testnets-chaindata.json`             | manual    | A list of all parachains and relay chains in the Polkadot ecosystem                           |
+| `chains-extras-cache.json`            | automatic | Caches static data for each substrate chain                                                   |
+| `evm-networks.json`                   | manual    | List of EVM chains supported by default in Talisman                                           |
+| `known-evm-networks.json`             | automatic | List of EVM networks, generated from [ethereum-lists](https://github.com/ethereum-lists)      |
+| `known-evm-networks-overrides.json`   | manual    | Overrides to `known-evm-networks.json`, matched by chain id                                   |
+| `known-evm-networks-icons-cache.json` | automatic | Caches images for each network defined in [ethereum-lists](https://github.com/ethereum-lists) |
+| `known-evm-tokens-cache.json`         | automatic | Caches static data for ERC20 tokens                                                           |
+| `tokens-buyable.json`                 | manual    | List of tokens displayed in Talisman's Buy Tokens form                                        |