[FEATURE] 1rst version of a CUE-based Dashboard-as-Code framework

[AntoineThebaud]

Description

This PR brings a first version of what we can call a Dashboard-as-Code framework. More precisely:

• helper libs, available at cue/dac-utils
• helper script for dependencies setup (no real dependency management available in CUE for the moment so have to go this way as a workaround..)
• user guide

Besides, for the "internal" part of this PR:

• new target cue-gen added to Makefile to generate the CUE definitions from to the Golang datamodel. This is needed for the DaC framework validation (= new tests associated to cue-test target)
• to better organize the code I gathered the new DaC utilities & existing plugin schemas in a new cue folder at the root, so I had to update many files to update the schemas paths accordingly.
• CUE definition patches, in order to fill the gaps of the cue get go generation (see comments in the files for more details)

Checklist

• Pull request has a descriptive title and context useful to a reviewer.
• Pull request title follows the [<catalog_entry>] <commit message> naming convention using one of the
  following catalog_entry values: FEATURE, ENHANCEMENT, BUGFIX, BREAKINGCHANGE, DOC,IGNORE.
• All commits have DCO signoffs.

[Nexucis]

Amazing work already !

I think we can simplify the setup by saving in the perses repo the cue files generated and by adding a dac subcommand in the CLI !

[Nexucis]

to ease the cross platform support, why not including that in the CLI ?

like under the command percli dac init --language=cue

[AntoineThebaud]

Yes since we already planned to add such dac subcommand in the CLI for other stuff, I was thinking of something like this but for a next PR, but yes we can already do this move if you want

[Nexucis]

so cool, that's a really nice start !!

As a side note I think you need to re-generate the cue files with the new URL type we added in the pkg /model/api/v1/common