feat(packages): add commons package

This is an import of 166ca8da12
with some changes to make it fit into the mono repo.
- TypedEventEmitter has been replaced with EventEmitter2 because EventEmitter2 is faster and TypedEventEmitter had some troubles with the new way of compiling.
- tsc-esm has been replaced with microbundle. The problems that lib0 doesn't export its types correctly has been solved using yarn patch.

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

.github/actions/setup-node/action.yml

@@ -36,3 +36,8 @@ runs:
       run: yarn install --immutable
       working-directory: .
       shell: bash
+
+    - name: Build commons lib
+      run: yarn build
+      working-directory: commons
+      shell: bash