ci: auto trigger major workflows on release branches

[Julio-Guerra]

What does this PR do?

1. Automatically run the important workflows on release-v* branches
2. Remove the release automation workflows which no longer work due to https://github.com/orgs/community/discussions/25305 when we recently reinforced our repo settings.

Motivation

Ease the release process and documentation.

Describe how to test/QA your changes

Reviewer's Checklist

• If known, an appropriate milestone has been selected; otherwise the Triage milestone is set.
• Changed code has unit tests for its functionality.
• If this interacts with the agent in a new way, a system test has been added.

[knusbaum]

Good idea to run these on release branches. However, where do the results go? Do we get alerted on failures or do we have to go and find the runs for the release branches and check them?

[pr-commenter]

Benchmarks

Comparing candidate commit 1e27f20 in PR branch julio.guerra/release-workflows with baseline commit cb93051 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 6 cases.

[Hellzy]

The person that pushes to the branch should get the notification as long as they subscribe to GH actions notifications, we - go guild members - won't get automatically alerted on the other hand.
I'm thinking that it's fine since this only impacts release branches, that are push protected.