[FEATURE]: Merge all of the pipelines into one

[piotrpdev]

Details

Is your feature request related to a problem? Please describe.

• Having to trigger several different pipelines is annoying for the end user.
• It is difficult to transfer information between pipelines in Tekton.
• It is difficult to trigger pipelines from other pipelines in Tekton.

Fixes #68

Describe the use-case or expected workflow

The user doesn't have to trigger several separate pipelines, instead they only trigger one. All of the pipeline-related work is done in one pipeline.

Describe alternatives you've considered

After looking into it, it seems the experimental Pipelines in Pipelines Tekton feature is much more underdeveloped than I thought. This is the approach I suggested in #68 (comment), however it seems like it won't be feasible any time soon.

Additional context

I still hold my concerns from #68 (comment), but I think this is a necessary choice to progress the PoC.

Considering that "Tekton indeed doesn't really offer any easy way to trigger one pipeline from another" and the issues we've been having keeping the pipelines separate (e.g. #137 (comment)) I now agree with @adelton's suggestion to merge the pipelines into one.