4.1.x Backport: Add ORT/atstccfg Deterministic Config Generation (#4557)

[rob05c]

• Make ORT gen deterministic

• Add ORT/atstccfg Line-Comment header

Adds a header to the multipart file, with the line comment syntax of
the file (if it has one).

This lets ORT safely strip line comments with times for diffing.

• Remove ORT/atstccfg unnecessary io param

Removes TCCfg from GetAllConfigs, making the function Pure, which
makes it possible/easier to unit test.

• Change ORT/atstccfg magic string to const

• Add ORT/atstccfg unit test for determinism

(cherry picked from commit d74de45)

What does this PR (Pull Request) do?

• This PR fixes #REPLACE_ME OR is not related to any Issue

Which Traffic Control components are affected by this PR?

• CDN in a Box
• Documentation
• Grove
• Traffic Control Client
• Traffic Monitor
• Traffic Ops
• Traffic Ops ORT
• Traffic Portal
• Traffic Router
• Traffic Stats
• Traffic Vault
• CI tests

What is the best way to verify this PR?

If this is a bug fix, what versions of Traffic Control are affected?

The following criteria are ALL met by this PR

• This PR includes tests OR I have explained why tests are unnecessary
• This PR includes documentation OR I have explained why documentation is unnecessary
• This PR includes an update to CHANGELOG.md OR such an update is not necessary
• This PR includes any and all required license headers
• This PR ensures that database migration sequence is correct OR this PR does not include a database migration
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

Additional Information