Asset Manager

We need an interface for managing all assets that are uploaded to a site managed by Beacon.

I'd prefer that the asset manager does not permit directories. It should be a flat file system that allows for the following

- IMAGE OPTIMIZATION:
- [x] Converting to .WEBP BeaconCMS/beacon#124
- [x] Smart image crop & scale BeaconCMS/beacon#198
- [x] Thumbnailing BeaconCMS/beacon#199
- [x] upload new asset BeaconCMS/beacon#197
- [x] delete existing asset (soft delete, hard delete after a period of time... maybe 96 hours?) BeaconCMS/beacon#200
- [ ] renaming of asset filename (don't allow for file extension rename) BeaconCMS/beacon_live_admin#24
- [x] search - a live search to filter by name BeaconCMS/beacon#202
- [ ] filter - filter by asset type (All, Image, Font, PDF, etc...) BeaconCMS/beacon_live_admin#20
- [ ] sort - by upload date, name, type BeaconCMS/beacon_live_admin#21
- [ ] used? - we should be able to show a list of all assets that are currently not in use BeaconCMS/beacon_live_admin#22
- [ ] which pages using - we should be able to show which pages are using a given asset, maybe even a grouping feature BeaconCMS/beacon_live_admin#23
- [x] attributes for assets BeaconCMS/beacon#208

This should be a LiveView UI and available/unique per-site in Beacon

Assets should be stored in the database as binary data types