feat(global-header): initial PR for global header plugin

[ciiay]

Hey, I just made a Pull Request!

Initial PR for RHIDP-5251

✔️ Checklist

• A changeset describing the change and affected packages. (more info)
• Added or Updated documentation
• Tests for new functionality and regression tests for bug fixes
• Screenshots attached (for UI changes)

Screen recordings

plugins/global-header test

rhidp_5251.mp4

dev env test

rhidp_5251_dev.mp4

[rhdh-gh-app]

Changed Packages

Package Name	Package Path	Changeset Bump	Current Version
app	workspaces/global-header/packages/app	none	v0.0.0
backend	workspaces/global-header/packages/backend	none	v0.0.0
@red-hat-developer-hub/backstage-plugin-global-header	workspaces/global-header/plugins/global-header	none	v0.0.0

[christoph-jerolimov]

Thanks, a great initial PR. 👍

Some small comments below and I think it's worthful if you can also address here:

1. Add a line to .github/CODEOWNERs :)
2. Please add a backstage app. I think its in general a good way to test plugins, but it's esp. useful for this plugin.
3. Address my comments below and (optional if you really want do that in a follow-up PR, but I think there no reason to rush ;)) split the GlobalHeader file a bit and remove the examples components.

[christoph-jerolimov]

Would be great if you can take a look into the comments below.

Here or in a follow up PR is up to you. But since you should also check why the build is failing, it's maybe easier to address them here directly.

Everything else looks nice!

[christoph-jerolimov]

@ciiay for the typescript errors in node_modules (duplicate type or something) we changes some of the workspaces to skipLibCheck (that means it doesn't validate node_module TS definitions):

➜ ~/git/redhat-developer/rhdh-plugins (main) ✔ grep skipLibCheck workspaces/*/package.json

workspaces/bulk-import/package.json:    "tsc:full": "tsc --skipLibCheck true --incremental false",
workspaces/homepage/package.json:    "tsc:full": "tsc --skipLibCheck false --incremental false",
workspaces/lightspeed/package.json:    "tsc:full": "tsc --skipLibCheck true --incremental false",
workspaces/marketplace/package.json:    "tsc:full": "tsc --skipLibCheck false --incremental false",
workspaces/openshift-image-registry/package.json:    "tsc:full": "tsc --skipLibCheck true --incremental false",
workspaces/orchestrator/package.json:    "tsc:full": "tsc --skipLibCheck true --incremental false",
workspaces/repo-tools/package.json:    "tsc:full": "tsc --skipLibCheck false --incremental false",
workspaces/theme/package.json:    "tsc:full": "tsc --skipLibCheck false --incremental false",

It's somehow related to a Node.js type and and some library type mismatches. It's fine to disable that check here as well.