Plex Cluster: Beta Testers Needed

Hi everyone,

You've been mentioned because at some point you have posted an issue here or participated via PR. I am migrating away from `plex-db-sync` to a new "instant sync" software platform I've developed called `Plex Cluster`.

I am looking for beta testers for the below platform. Reply here if you are interested!

## Features
- Syncs watched status on-demand, right away
- Uses standard Plex APIs without accessing the database
- Can work across multiple Plex servers
- Scheduled "full update" can completely sync user's watched status for any user that has been active on each Plex server since running `Plex Cluster`
- Syncs media that is contained on both (or multiple) servers without erroring when media does not exist
- Works for Plex.tv or Managed users

## Architecture
Plex Cluster contains two applications:
- **Plex Cluster Proxy**, which is installed alongside every Plex server and acts as a proxy (using `nginx`) between Plex Media Server and the internet. This application's job is to pass any requests that come to it along to the Plex server while catching any requests that mark watched status and also forwarding them on the **Plex Cluster Manager**. There is one instance of `Plex Cluster Proxy` for each Plex server.
- **Plex Cluster Manager** is then used to synchronize the status between Plex servers. There is only one instance of `Plex Cluster Manager` which is used by all instances of `Plex Cluster Proxy`.

An example use case:
1. Plex client requests to watch a show with GIUD (unique identifier) `ABC` from the `TV Shows` library on `Plex Server 1`
2. The request goes through `Plex Cluster Proxy 1` and is passed along to `Plex Server 1`
3. The user stops the show midway.
4. The request goes through `Plex Cluster Proxy 1` and is passed along to `Plex Server 1`, but is also passed along to `Plex Cluster Manager`
5. `Plex Cluster Manager` takes the request and checks for any other Plex server with a library named `TV Shows` and GUID `ABC`
6. For any other servers it finds, such as `Plex Server 2`, it forwards the request on to them and the show is instantly marked as watched up to that midway point.
7. User switches over to `Plex Server 2` and sees that they are midway through show `ABC`

@ChaosZero112 @daxxi13 @Malcolmest @seertenedos @skinnyzaz @sbcrumb @goofballtech @onezero1010101 @ddurdle @dpeet