TS migration. #2288. (#2328)

* Added TS. Updated build and linting config. Added types.

* [ts-migrate][.] Rename files from JS/JSX to TS/TSX

Co-authored-by: ts-migrate <>

* [ts-migrate][.] Run TS Migrate

Co-authored-by: ts-migrate <>

* Corrected files mangled by ts-migrate.

* Updated lint config, minor linting.

* Re-enabled Husky.

* Updated tests and config.

* Reverted webpack devtool config.

* Removed obsolete snapshots.

* Added annotations snap.

* Updated tsconfig includes wrt linting.

* Removed ts-migrate.

Co-authored-by: Timmy Huang <tihuan@users.noreply.github.com>

client/configuration/webpack/webpack.config.shared.js

@@ -29,6 +29,9 @@ module.exports = {
     path: path.resolve("build"),
     publicPath,
   },
+  resolve: {
+    extensions: [".ts", ".tsx", "..."],
+  },
   module: {
     rules: [
       {