MTNI-113 ⁃ Change of database in DAT

[blackforestboi]

Just had a call with Alexander Praetorius, who gave me a lot of good tips for libraries we can use instead of pouchDB and adapters to use for DAT.

Just leaving them here, so we can discuss about them, also related to the sharing network:

https://github.com/beakerbrowser/hashbase (https://hashbase.io/)
https://github.com/mafintosh/hypercore
https://github.com/mafintosh/hypervision
https://github.com/mafintosh/hyperdb (alternatively: https://github.com/beakerbrowser/injestdb)
https://github.com/levelgraph/levelgraph as a graph database (alternatively gun.js.org, however the latter is a separate application which does not integrate so)

hyperdb, injestdb,levelgraph, hypercore and hashbase modularly integrate/build on top of each other very well with leveldb, so we can use it in the browser's native database + on the server as well.

[swissums]

This will be dealt with at a later stage.