Installing / configuring mongodb

Install mongodb server ("mongod") and mongodb client ("mongo", but there are also GUI clients) (these are usually in one package)
if necessary: change spring.data.mongodb.* in application.properties
use (databases are automatically created :-))

Getting started

run a basic use case:
- run org.freeplane.server.Application (as Java Application) from server repo
- run freeplane-osgi launcher from freeplane repo
  - select the websockets check box
  - click button -> message interchange is triggered

One client
- Connect to server (web socket session) check
- Create a new map on server and get its uuid check
- Send updates to server and receive them back
- Subscribes to updates for a given map id
- Receives all updates from server for a given map id
  - From the beginning
  - From given map revision
  - Optimize: server skips overwritten updates of the same element (later)
Many clients
- Servers orders all updates from all clients, server changes map revisions for later updates if necessary
- Server checks for conflicts in updates having the same map revision in the input events and notifies clients (later)
OAuth2 authentication
- Check authentication (full access for any clients with valid credentials, may be JWT tokens)
- Manage write and read permissions for a map (API or browser app ?)

** Other issues * Extract events and serialization in a separate project to be used from both client and server check