FEMT: Call /bootdata and render grafana (#105176)

* rename /mtfe route to /femt to match project name

* set correct navTree JSON property name

* call GetWebAssets in the request handler to prevent stale assets during development

* Call /bootdata and render grafana

* set nonce on script

* write csp header in index handler

* write report-only csp as well

* debug stuff

* more debug logging

* move importing app into a seperate, async-loaded module

* Clean up comments

* make /femt redirect to / in the frontend

* remove console.log

* remove stale commented code

* call __grafana_load_failed if bootstrap fails

* comment for __grafana_boot_data_promise

* remove console.log

* remove blank newline

* codeowners

.github/CODEOWNERS

@@ -605,6 +605,7 @@ playwright.config.ts @grafana/plugins-platform-frontend
 /public/app/dev.ts @grafana/frontend-ops
 /public/app/core/utils/metrics.ts @grafana/plugins-platform-frontend
 /public/app/index.ts @grafana/frontend-ops
+/public/app/initApp.ts @grafana/frontend-ops
 /public/app/AppWrapper.tsx @grafana/frontend-ops
 /public/app/partials/ @grafana/grafana-frontend-platform