Remodel solvers

[anxolin]

Improves the modeling of solvers.

Moves the addresses from the solver entity to a new solver-network one. This way, we avoid replication of data.

These are the changes

Add environments

We add a master record for the environments

Remove addresses and networks from solver

This info has been moved

Create new Solver-Network entity

This entity maps a solver, to a network and a environment. It includes information about the address and payoutAddress

Test

Run it locally and test creating a few solvers and solver networks