Tech debt: devfilev2 and master branch cleanup in che-samples repos

[nickboldt]

Is your task related to a problem? Please describe

Today the che-samples repos have both a CURRENT, maintained devfilev2 branch, and a default master or main branch:

https://github.com/che-samples/web-php-simple
https://github.com/che-samples/web-nodejs-sample
... (others)

Describe the solution you'd like

Since devfile v1 is no longer the default / no longer really supported... should we:

• make the devfilev2 branch the new default branch for these sample projects?
• force-push the contents of the devfilev2 branches into main
• if the project doesn't have a main branch (only an obsolete master branch), simply rename devfilev2 to main ?
• update references to the devfilev2 branch to use main instead, eg., https://github.com/eclipse-che/che-website/blob/main/src/lib/try/TryOnline.svelte#L53
• update devfile registry to reference new branches

Or do the sample projects all get migrated to devfile.io?

[svor]

Default branch in che-samples repositories contain devfile v1 and I don't think we use it in any place. Since we completely switched to devfile v2, I'd combine and apply these two options:

force-push the contents of the devfilev2 branches into main
if the project doesn't have a main branch (only an obsolete master branch), simply rename devfilev2 to main