ci: trigger workflows for PRs with ok-to-test label

[thesuperzapper]

This PR:

1. Adds a new workflow that will trigger workflows for PRs that have the ok-to-test label
2. Cleans up some of the existing workflow names/permissions/formatting
3. Makes it so we run backend/controller tests if changes are made to either (as they depend on each other)

[ederign]

/lgtm

[ederign]

/approve

[thesuperzapper]

/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ederign, thesuperzapper

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