E2E: Add support for building test plugins (#91873)

* build test apps with webpack

* add extensions test app

* update e2e tests

* remove non-build test apps using amd

* use @grafana/plugin-configs rather than create-plugin config

* Update e2e/plugin-e2e/plugin-e2e-api-tests/as-admin-user/extensions/usePluginComponents.spec.ts

Co-authored-by: Jack Westbrook <jack.westbrook@gmail.com>

* Update package.json

Co-authored-by: Jack Westbrook <jack.westbrook@gmail.com>

* use run dir variable instead of hardcoded path

* add dummy licence file

* add separate step for building test plugins

* support nested plugins

* remove react-router-dom from the externals array

* remove add_mode dev

* lint starlark

* pass license path as env variable

* fix the path

* chore(e2e-plugins): clean up dependencies to match core versions

* refactor(e2e-plugins): prefer extending webpack plugins-config

* docs(e2e-plugins): add basic info to extensions test plugin readme

* update readme

* change dir name from custom plugins to test plugins

* change root readme

* update lockfile

---------

Co-authored-by: Jack Westbrook <jack.westbrook@gmail.com>

scripts/grafana-server/start-server

@@ -23,8 +23,9 @@ fi
 echo starting server
 
 cp -r ./bin $RUNDIR
-cp -r ./public $RUNDIR
 cp -r ./tools $RUNDIR
+ln -s $(realpath ./public) $RUNDIR
+
 
 mkdir $RUNDIR/conf
 mkdir $PROV_DIR
@@ -39,12 +40,12 @@ cp ./conf/defaults.ini $RUNDIR/conf/defaults.ini
 echo -e "Copying custom plugins from e2e tests"
 
 mkdir -p "$RUNDIR/data/plugins"
-# when running in a local computer
-if [ -d "./e2e/custom-plugins" ]; then
-  cp -r "./e2e/custom-plugins" "$RUNDIR/data/plugins"
+
+if [ -d "./e2e/test-plugins" ]; then
+  ln -s $(realpath ./e2e/test-plugins/*) "$RUNDIR/data/plugins"
 # when running in CI
-elif [ -d "../e2e/custom-plugins" ]; then
-  cp -r "../e2e/custom-plugins" "$RUNDIR/data/plugins"
+elif [ -d "../e2e/test-plugins" ]; then
+  cp -r "../e2e/test-plugins" "$RUNDIR/data/plugins"
 fi
 
 echo -e "Copy provisioning setup from devenv"