Patch/performance fixes

[jclausen]

Description

This PR resolves several performance issues seen in the wild:

• getActiveContent has been refactored to allow an asString boolean arg. When passed as true this will execute a projection list query to retrieve the content string only. This is demonstrating a significant performance improvement - especially when ContentStore items contain JSON which is exposed directly from the API
• A read-only activeContentVersions property has been added to prevent retrieval of all versions. This is a significant performance improvement when the content item has a large number of revisions, compared to looping all versions.
• The fetch="join" attribute has been removed from the ContentVersion relatedContent relationship as this is mutually exclusive to lazy="true" the queries being executed when retrieving content items alone were producing the join, but also the joins from the BaseContent and were significantly increasing version entity retrieval times.

Type of change

Please delete options that are not relevant.

• Improvement

Checklist

• My code follows the style guidelines of this project cfformat
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[lmajano]

good call!