Make __map private

[julianrex]

PRs must be submitted under the terms of our Contributor License Agreement CLA.

Fixes: < Link to related issues that will be fixed by this pull request, if they exist >

Pull request checklist:

• Briefly describe the changes in this PR.
• Include before/after visuals or gifs if this PR includes visual changes.
• Write tests for all new functionality. If tests were not written, please explain why.
• Add example if relevant.
• Document any changes to public APIs.
• Apply changelog label ('breaking change', 'bug 🪲', 'build', 'docs', 'feature 🍏', 'performance ⚡', 'testing 💯') or use the label 'skip changelog'
• Add an entry inside this element for inclusion in the mapbox-maps-ios changelog: <changelog></changelog>.
• Update the migration guide, API Docs, Markdown files - Readme, Developing, etc

Summary of changes

• Made MapboxMap.__map private
• Update CircleCI to use derived data directory for MapboxMaps xcodeproj testing
• Re-enable code coverage (except for codecov.io)
• Added
  • CameraManagerProtocol .setCameraBounds
  • MapboxMap.prefetchZoomDelta
  • MapboxMap.options to return the current MapOptions
  • MapboxMap.reduceMemoryUse()
  • MapboxMap.resourceOptions
  • MapboxMap.elevation(at:)
• Removed OfflineError.invalidResult and OfflineError.typeMismatch

In the MapboxMaps Xcode project, MapboxMaps is built as a dynamic framework, including its dependencies using SPM. These end up as sub-frameworks when built, which AWS Device Farm does not appear to re-code-sign. Prior to upload these sub-frameworks are moved to being child frameworks of the test host application.

Attempting to add the dependencies to the host application results in an error regarding "duplicated code" even though these are dynamic frameworks. This appears to be a known issue. Explicitly marking the dependencies as dynamic may solve this issue.