[camera] android-rework part 7: Android noise reduction feature

[BeMacized]

Adds the noise reduction feature containing the implementation to handle setting noise reduction levels via the Android Camera2 API.

This is the seventh PR in a series of pull-requests which will gradually introduce changes from PR #3651, making it easier to review the code (as discussed with @stuartmorgan).

Pre-launch Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• I read and followed the [Flutter Style Guide] and the [C++, Objective-C, Java style guides]. (Note that unlike the flutter/flutter repo, the flutter/plugins repo does use dart format. See [plugin_tool format])
• I signed the [CLA].
• The title of the PR starts with the name of the plugin surrounded by square brackets, e.g. [shared_preferences]
• I listed at least one issue that this PR fixes in the description above.
• I updated pubspec.yaml with an appropriate new version according to the [pub versioning philosophy].
  • Since this will be a series of pull-requests I will update the version in the last PR of the series.
• I updated CHANGELOG.md to add a description of the change.
  • Since this will be a series of pull-requests I will update the version in the last PR of the series.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making or feature I am adding, or Hixie said the PR is test exempt.
• All existing and new tests are passing.

[mvanbeusekom]

Looks good, just needs documentation for two public methods. Also the format step in tree seems to be failing.

[mvanbeusekom]

Some of the newly added files are using the incorrect license header which causes the format step in the tree to fail.

[mvanbeusekom]

LGTM!