[minor] Overhaul FVT pipeline integration

[durera]

Start to use pipelines in pipelines to begin to bring install / install-with-fvt back closer to one another. Install with FVT pipeline will have a few additional "kick off" tasks that launch completely separate FVT pipelines.

Also:

• Simplify assist pipeline build (remove unnecessary templating)
• Introduce dedicated Core FVT pipeline
• Introduce dedicated Assist FVT pipeline
• Introduce dedicated Manage, Manage IS, Manage Mobile, and Manage Regression FVT pipelines
• Update build-tekton.sh to support build of tasks or pipelines only using $1 arg set to tasks or pipelines

[alequint]

@durera it may be better if we could merge this PR #614 before this one. It is a small quick fix for a problem introduced when cv-app tests were onboarded, related to the different run-after of ivtcore and, now, cv, when running in install-with-fvt and when running in fvt-manage.

this is more to get things right from start in this reorg.... or is too late? :)

[durera]

@durera it may be better if we could merge this PR #614 before this one. It is a small quick fix for a problem introduced when cv-app tests were onboarded, related to the different run-after of ivtcore and, now, cv, when running in install-with-fvt and when running in fvt-manage.

this is more to get things right from start in this reorg.... or is too late? :)

I would just close that PR, and take a look whether the same problem exists in the updated manage pipelines here as it's not 1:1 ... eg. manage-regr pipeline is just the manage regression tasks for example.