[docker] remove (redundant) chmod and testable workflows

[TrevorBenson]

Description

• Removes the redundant chown from step 12, relying on the final one in step 20.
• Adds new workflow inputs
  • guild_deploy_branch which defaults to master
  • testing which defaults to false
• Conditional logic on the push operation
  • If branch is master and testing is false, the push will occur.
  • If branch is master but testing is true, the push will not occur
  • If branch is NOT master, but testing is falase, the push will not occur (prevents mistaken test from updating the public images).

Where should the reviewer start?

Compare the two builds. Try a workflow dispatch with testing true, and with branch not set to master.

Motivation and context

An error in build process when no shell scripts exist in /home/guild/.scripts/ when the operation occurs. Allows testing of the branches for docker building similar to pre-merge testing of changes to guild-deploy.sh etc.

Which issue it fixes?

Closes #1709

How has this been tested?

Local build, and workflow job

[TrevorBenson]

I didn't dig deep enough in the prior PR #1707 to notice this wasn't Ogmios-related, and it was dropped along with the Ogmios change. Unsure which actual commit it comes from as I have a container built from the #1676 PR. So I (or possibly someone else) may have introduced it in a later commit.

Once the Ogmios change merges into master I'll use the workflow to confirm builds are working again for new Pull Requests. Otherwise, I may open a PR for the workflows that use a default master branch but allow a workflow dispatch to target the alpha branch as well to test prior to things merging into the master, as the current build logic makes it easy to run a test which appears to work but could be due to targetting master and not alpha.

[TrevorBenson]

I went ahead and merged the workflow inputs and logic into this branch, it made it easier to test everything together, confirm a failure on alpha and then the success on container-chown-error, the branch of this PR.