Integrate lsm-tree

[geo2a]

In preparation for LedgerHD and Leios, as well as to retire the LMDB backend for UTxO-HD, we need to integrate the lsm-tree library as the on-disk storage backend for UTxO-HD.

This is the meta-issue which we will use coordinate the integration effort.

Phase 0: getting the dependencies aligned

Currently, lsm-tree allows io-classes 1.6 and 1.7, but the Network packages are being upgraded from 1.5 directly to 1.8. io-classes 1.8 has introduced some breaking changes, so we have to update lsm-tree to 1.8 before we can integrate the library into Consensus, as we'll have to follow the Network and use io-classes 1.8.

The steps that are needed to start the integration process are the following:

• wait until Network has integrated io-classes 1.8. Seems like this is going to happen soon, see io-classes-1.8 ouroboros-network#4951.
• integrate io-classes 1.8 and io-classes 1.8-enabled Network into Consensus, as these task are intertwined I think
• integrate io-classes 1.8 into lsm-tree. This task could be done in-parallel with the previous two.

Phase 1:

• integrate lsm-trees into Consensus once everything uses io-classes 1.8

The description of this phase will be itemised further.