Add local dev command to run backend and plugin

[dsimansk]

Changes

• Add local page cmd to view

GitHub Pages local development - fetch('plugin.yaml') always fails locally because plugin.yaml is only generated by the CI workflow (helm template). Add a way to test the GitHub Pages site locally (e.g. a script that generates plugin.yaml into the pages directory, or a local dev server setup).

@matejvasek @twoGiants is this somewhat coming closer to the idea stated above?

[dsimansk]

After spending some time with local dev setup on CRC, I'm rethinking the very simple approach of separate command. I see it needs to be properly wired into local dev loop.