Grafana UI: Make it possible to bundle package with plugins (#76191)

* moved themecontext to data

* chore(grafana-ui): re-export ThemeContext from grafana/data for backwards compatibility

* Moved icon bundling to core.

* feat(plugins): share react-inlinesvg with plugins for grafana/ui bundling

* chore(codeowners): add generate-icon-bundle.js to file

* chore(storybook): update path to iconBundle file for theme

* feat(plugins): share i18n dependency via systemjs

* Make sure that icon bundle is initialized for tests.

* Removed comment.

* added tests for icon root.

* Removing the need of having an init variable.

* feat(grafana-ui): add icon svgs to bundle for projects that don't rely on grafana

---------

Co-authored-by: Marcus Andersson <marcus.andersson@grafana.com>

package.json

@@ -53,7 +53,8 @@
     "betterer": "betterer",
     "betterer:merge": "betterer merge",
     "betterer:stats": "ts-node --transpile-only --project ./scripts/cli/tsconfig.json ./scripts/cli/reportBettererStats.ts",
-    "betterer:issues": "ts-node --transpile-only --project ./scripts/cli/tsconfig.json ./scripts/cli/generateBettererIssues.ts"
+    "betterer:issues": "ts-node --transpile-only --project ./scripts/cli/tsconfig.json ./scripts/cli/generateBettererIssues.ts",
+    "generate-icons-bundle-cache-file": "node ./scripts/generate-icon-bundle.js"
   },
   "grafana": {
     "whatsNewUrl": "https://grafana.com/docs/grafana/next/whatsnew/whats-new-in-v10-1/",