[video_player] add setBitrate function

[apieceofcode1801]

Replace this paragraph with a description of what this PR is changing or adding, and why. Consider including before/after screenshots.

List which issues are fixed by this PR. You must list at least one issue.

If you had to change anything in the flutter/tests repo, include a link to the migration guide as per the breaking change policy.

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 relevant style guides and ran the auto-formatter. (Unlike the flutter/flutter repo, the flutter/plugins repo does use dart format.)
• [x] I signed the CLA.
• [x] 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, or this PR is exempt from version changes.
• [ ] I updated CHANGELOG.md to add a description of the change, following repository CHANGELOG style.
• [ ] I updated/added relevant documentation (doc comments with ///).
• [ ] I added new tests to check the change I am making, or this PR is test-exempt.
• [ ] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[AngeloAvv]

Hey @apieceofcode1801 do you need help with this feature? I'm interested in bringing these things in chewie to allow the user to pick the quality they want.

[apieceofcode1801]

Hey @apieceofcode1801 do you need help with this feature? I'm interested in bringing these things in chewie to allow the user to pick the quality they want.

I implemented setBitrate function in this PR, but I have no experience in creating PR for Flutter plugin so many checks are not passed. For these, I have not yet time to continue so I'm waiting to continue this feature later. If you can help to review, it's appreciated.

[Hixie]

@apieceofcode1801 Are you still interested in working on this one? If so, you may be able to get help by asking on #hackers-new in our Discord server (see link in the contributing guidelines). If you would like a review, marking this as ready for review (as opposed to draft) will bring it onto the radar of the people doing code review.

[stuartmorgan-g]

Since this is marked as a draft and hasn't been updated in several months I'm going to close it to clean out our review queue. Please don't hesitate to submit a new PR if you decide to revisit this. Thanks!