Mux-python

* Adds support for asset metadata
* Replaces `input` on CreateAssetRequest with `inputs`, which accepts the same type, and added deprecation notices
* Replaces `playback_policy` on CreateAssetRequest with `playback_policies`, which accepts the same type, and added deprecation notices
* Fixes the accepted type of UpdateReferrerDomainRestrictionRequest
* Changes the type of `new_asset_settings` in to be a CreateAssetRequest, which exposes the correct set of fields to control asset creation
* Adds creator id field to Mux Data

- add support for `static-renditions` APIs
- add `passthrough` to each `static_rendition` object
- add support for additional standard dimensions in Mux Data
- allow updating `video_quality` on live streams
- [breaking] It is very unlikely that you were using the `AssetStaticRenditionsFiles` type directly, but just in case this has been replaced with `StaticRendition` for the object, and `CreateStaticRenditionRequest` for the request with the new `static-renditions` APIs
- [breaking] Deprecate `mp4_support` and associated APIs. [Utilize the new Static Rendition APIs instead.](https://www.mux.com/docs/changelog/static-renditions-api-for-creating-mp4-and-m4a-renditions-now-available)
- [breaking] Remove Spaces APIs and routes

- Remove `ad_watch_time` and `view_content_watch_time`, metrics which do not exist.

*Note:* The above change may be considered breaking; if you were accessing either field on a base Video View, that will no longer work. It is highly likely that your code was not using those fields, however. Additionally, those metrics are no longer allowed in the metrics API.

- Deprecate `encoding_tier` and add support for `video_quality` to replace it
- Add support for `premium` video quality
- Add support for updating `master_access` settings on Live Streams
- Add support for `view_dropped` and `view_dropped_percentage`

- support `video_quality` setting in place of deprecated `encoding_tier`. [Read more](https://www.mux.com/blog/no-one-said-naming-was-easy-encoding-tiers-are-now-video-quality-levels)
- add support for DRM. [Read more](https://www.mux.com/blog/introducing-drm-the-latest-tool-in-protecting-your-content-on-mux)

- prepare for upcoming feature release
- update docs around default measurement