Remove Environments tab and clean up old code (#9237)

[keithchong]

See GITOPS-9237 for details. Looks like a lot of changes, but it's actually small because of refactoring

Here is the summary of the changes

1. Removed old code related to the old Environments page. This was in the src/components folder

• However, there is some that we still use / can use. They are 'plugin' related so I renamed the folder to plugin. This includes the code to set the flag, and tech preview badge (removed the DP badge)
• There is a status/icons.tsx file that I want to clean up separately, since it should really belong in the gitops folder and not this new plugin folder
• The Rollouts topology view support was in the src/components folder, so I simply moved it to the src/gitops folder and adjusted the references

3. Reran i18n to update the translation files to remove unused strings
4. There was inadvertant duplicate ExternalLink, so I got rid of one and updated the reference. (Safe, code change here). There should be the external link icon whenever there is a link to the external site. Now, all links have that icon.
5. package.json changes. There is an exposedModules section which was replaced by plugin-metadata.ts which is referenced by webpack.config.ts. I cleaned this up so we just use the latter. Tested this out, so the exposed modules are indeed exposed. Any modules that were reference code that was deleted was also removed.
6. console-extensions.yaml - removed the extensions that no longer apply since we are removing the environments page

[aali309]

Clicking the "Add to favorites" button looks broken