Description of the Change

This PR adds messaging to changelogs and readmes to alert folks to the pending change, currently listed as coming in the 3.7.0 release, of removing built assets from develop, building into a stable branch, and removing master in favor of trunk and removing built assets from trunk.

This PR only attempts to cover the first checkbox here: #2182 (comment). We'll want to mirror this messaging across future 3.6.* releases to continue communicating these pending changes. We'll also need to work through the additional checkboxes on #2181, happy to help with more there as desired.

Alternate Designs

Potentially adding messaging into other places across the codebase, or adjusting copy to be more precise.

Benefits

Ensures we attempt to alert as broad a base of users as possible ahead of making these changes.

Possible Drawbacks

None identified besides over communicating.

Verification Process

Verified via VS Code and GitHub Desktop UI.

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests passed.

Applicable Issues

Relates to #2182.

Changelog Entry

### Added
- Documentation updates (props @jeffpaul).