* Initial working grain
* Incremental work on actor bookmark management & resuming wokflows
* Upgrade Proto Actor package references
* Fix lifetime of actors
* Implement bookmark and resumption
* Update Program.cs
* Update bookmark event publishing
* Refactor proto actor features API
* Implement snapshotting
* Update snapshotting
* Add in-memory provider and use it by default
* Update server bundle to use proto actor sqlite persistence by default
