feat(lib/trie): cache inserted trie node Merkle values

[qdm12]

Changes

• Production code changes
• Fixes all tests
• Change delta tracking to use node pointers to improve performance
• Remove dirty bool field
• Create issue for child tries delta tracking

Tests

go test -tags integration github.com/ChainSafe/gossamer/lib/trie/...

Issues

Fixes #2854 and unblocks lazy loading impl

Primary Reviewer

[qdm12]

This is simply not possible in terms of cpu performance.
Re-calculating the merkle value (scale encoding + blake2b) of N nodes when inserting a node at depth N in the trie is too expensive to be a working solution. This also highlights the need for:

• lazy-hashing: only compute the state root of the trie when needed, and not on every insertion (already the case in our code)
• lazy loading needs a write cache, meaning we keep deltas in a in-memory part of the trie without encoding/hashing/writing to disk, and only do the root hash computation + write of deltas when needed (i.e. at the end of handling a block).

Closing this for now as a failed but taughtful experiment.