Migrate app to TypeScript (#1637)

* Initial setup and migrated src/common

* WIP

* WIP

* WIP

* Main module basically finished

* Renderer process migrated

* Added CI step and some fixes

* Fixed remainder of issues and added proper ESLint config

* Fixed a couple issues

* Progress!

* Some more fixes

* Fixed a test

* Fix build step

* PR feedback

.circleci/config.yml

@@ -108,6 +108,7 @@ jobs:
           apt_opts: "--no-install-recommends"
       - restore_cache:
           key: lint-{{ arch }}-{{ .Branch }}-{{ checksum "package-lock.json" }}
+      - run: npm run check-types
       - run: ELECTRON_DISABLE_SANDBOX=1 xvfb-run npm run test
       - run: mkdir -p /tmp/test-results
       - run: cp test-results.xml /tmp/test-results/