feat: restructure Part2 database crate

[rakita]

cargo depgraph --no-default-features --workspace-only | dot -Tpng > graph.png

[github-actions]

Valgrind Results:

==4462== Cachegrind, a cache and branch-prediction profiler
==4462== Copyright (C) 2002-2017, and GNU GPL'd, by Nicholas Nethercote et al.
==4462== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==4462== Command: target/release/revme bench snailtracer
==4462== 
--4462-- warning: L3 cache found, using its data for the LL simulation.
Running snailtracer example!
elapsed: 1.863090771s
==4462== 
==4462== I   refs:      429,377,938
==4462== I1  misses:          5,448
==4462== LLi misses:          4,163
==4462== I1  miss rate:        0.00%
==4462== LLi miss rate:        0.00%
==4462== 
==4462== D   refs:      205,674,403  (133,128,441 rd   + 72,545,962 wr)
==4462== D1  misses:        346,580  (    203,877 rd   +    142,703 wr)
==4462== LLd misses:        142,399  (      7,266 rd   +    135,133 wr)
==4462== D1  miss rate:         0.2% (        0.2%     +        0.2%  )
==4462== LLd miss rate:         0.1% (        0.0%     +        0.2%  )
==4462== 
==4462== LL refs:           352,028  (    209,325 rd   +    142,703 wr)
==4462== LL misses:         146,562  (     11,429 rd   +    135,133 wr)
==4462== LL miss rate:          0.0% (        0.0%     +        0.2%  )