Migrate @metamask/eth-json-rpc-provider - Phase B: Staging from merged-packages/ #1792

As part of the process for migrating @metamask/eth-json-rpc-provider into the core monorepo, we need to execute various preparation steps while the package is inside of the temporary merged-packages/ directory, before it can be moved into the packages/ directory.

See #1551 (comment) for an outline of the entire process.

Phase B: Staging from merged-packages/

1. Remove files and directories that will be replaced by files in the monorepo root.

• eth-json-rpc-provider migration - B1: Remove redundant files and directories. #1764
  • Remove: .github/, .git*, scripts/, .depcheckrc.json, .yarn/, .yarnrc.yml, yarn.lock, .editorconfig, .eslint*, .prettier*, .nvm*.
  • Keep: src/, tests/, CHANGELOG.md, LICENSE, package.json, README.md, jest.config.js, tsconfig*.json, typedoc.json.

2. Replace config files.

• eth-json-rpc-provider migration - B2: Replace typescript, jest config files. #1765
  • Update tsconfig*.json, typedoc.json, jest.config.js to extend from corresponding files in root. Copy contents of corresponding files in other non-root packages.
  • Keep TypeScript compiler flags.
  • Add tsconfig reference paths for non-root packages that are upstream dependencies of the migration target.
  • Keep Jest coverage threshold values.
  • Add deepmerge as a devDependency.

3. Align dependencies with monorepo.

• eth-json-rpc-provider migration - B3: Align dependencies with monorepo. #1766
  • Remove redundant dependencies that are already listed in the root package.json.
  • Bump remaining dependency versions so that they align with other non-root packages.

4. Add exception for non-MIT license.

• eth-json-rpc-provider migration - B4: Add exceptions in constraints.pro for ISC license. #1767
  • If migration target uses a non-MIT license, add exception entries in the root constraints.pro file.
  • Make sure the new rule doesn't break any of the existing package.json files by running yarn constraints.