Make feature-flags config map name customizable

[jerop]

The config maps used by Tekton Pipeline should be able to take custom
names to avoid collisions with other services.

However, the feature-flags config map wasn't customizable because its
name hardcoded its usages.

By defining an env var in controller.yaml, from which the feature-flags
config map name can be derived, we enable it to be customizable.

Fixes #1805.

Changes

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Release Notes

feature-flags config map name can be specified by the user

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[tekton-robot]

Hi @jerop. Thanks for your PR.

I'm waiting for a tektoncd member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[jerop]

/assign @dibyom

[googlebot]

CLAs look good, thanks!

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[vdemeester]

/ok-to-test

[ghost]

/approve

[ghost]

I've seen the TestHelmDeployPipelineRun integration test error out across a couple of PRs but then it sometimes seems to work. Trying a rerun.

/test pull-tekton-pipeline-integration-tests

[eddycharly]

@sbwsg what is this test doing ?
Are there some helm charts already available somewhere ?

[ghost]

I've created #2367 for investigating the helm integration test issue further.

[dibyom]

/lgtm

Thank you! I think in a follow-up PR we can move the FeatureFlags related functionality to its own package (related: #2117)

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dibyom, sbwsg

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[bobcatfish]

Hey @jerop could we add some docs for this as well? Normally we try to include docs for new features we add in the same PR, in this case maybe https://github.com/tektoncd/pipeline/blob/master/docs/install.md

[bobcatfish]

ps. some more info (very brief tho) about docs in every PR: https://github.com/tektoncd/community/blob/master/standards.md#principles

[jerop]

@bobcatfish sure! i'll add docs