Make it possible to read all checkpoints of a partitioning

[benedeki]

Background

Atum is to provide read abilities too, not just write

Goal

We need to be able to read saved checkpoint data of a given partitioning.

Tasks

Beta Give feedback

1. Figure out a preferable way to return checkpoints data. #177
   0 of 5
   DB question +2
   
2. Create DB function to get all checkpoint data of a partitioning #189
   DB enhancement work in progress +3
   
3. Create Server endpoints (v2) returning the checkpoins data of a partitioning #190
   Model Server enhancement +3
   
4. Add the ability to AtumAgent (maybe, depending on How to read information stored by Atum server? #179 )

[lsulak]

Done! Not part of Agent yet as we talked that we'll only add it if / after a while, if it will be convenient for our users / usage of it.