Fix inserts remove leaks

[cchudant]

• Added proptest
• Proptest showed a number of fun bugs, which I fixed
• Added a check to see if trie nodes are leaked to the proptest, which showed me a lot of cases where they are not, which i fixed
• Node type Unresolved was removed (init_tree does nothing now)
• The bonsai trie now syncs properly with sepolia and mainnet

Smallvec pr should be merged before this one, and i'll rebase this one afterward on main
Opening as draft because bonsai log is probably broken, i havent tested, and uncommited tx needs to be fixed -- I don't have time to fix those at the moment

@AurelienFT

[cchudant]

closes #31