chore: remove un-required version number and tidy docs

[jaredfholgate]

Overview/Summary

This PR removes a version number that is no longer required. The ALZ PowerShell module now handles the version. The config setting need to be retained in the config.json for the time being.

This PR fixes/adds/changes/removes

1. env file is generating wrong UPSTREAM_RELEASE_VERSION #684 (The actual fix is in bug: upstream release version env var ALZ-PowerShell-Module#88), but this is part of the same thing

Breaking Changes

1. None

Testing Evidence

Generated env file now contains the correct version even when pulling the wrong config.

As part of this Pull Request I have

• Read the Contribution Guide and ensured this PR is compliant with the guide
• Ensured the resource API versions in .bicep file/s I am adding/editing are using the latest API version possible
• Checked for duplicate Pull Requests
• Associated it with relevant GitHub Issues
• (ALZ Bicep Core Team Only) Associated it with relevant ADO Items
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated one or more of the following tests (if required)
  • Unit
  • Linting
  • E2E (End-To-End)
  • ValidateAzCloud (Base validation in Azure Cloud)
  • ValidateMcCloud (Base validation in Azure China Cloud)
• Updated relevant and associated documentation (e.g. Contribution Guide, Module READMEs, Wiki Docs etc.)
• If relevant, created or updated Code Tours here