chore: increase max dbs

[onbjerg]

Currently it's not possible to create custom tables if you re-use reth because MDBX needs to be hinted how many tables ("databases") there can ever exist.

This is a breaking change because:

Controls the maximum number of named databases for the environment.

By default only unnamed key-value database could used and appropriate value should set by MDBX_opt_max_db to using any more named subDB(s). To reduce overhead, use the minimum sufficient value. This option may only set after mdbx_env_create() and before mdbx_env_open().

Link

As a follow up, an example of using a custom table could be added. However, it is important to note that this would only work if the database is completely within the control of the developer, i.e. it cannot be a sidecar process because of MDBX limitations on 1 write tx per environment.

[codecov]

Codecov Report

Merging #4381 (aa50e96) into breaking-changes (72b211e) will increase coverage by 0.00%.
Report is 187 commits behind head on breaking-changes.
The diff coverage is 66.66%.

❗ Current head aa50e96 differs from pull request most recent head 85ed637. Consider uploading reports for the commit 85ed637 to get more accurate results

Files Changed	Coverage Δ
crates/storage/db/src/implementation/mdbx/mod.rs	97.44% <66.66%> (+<0.01%)	⬆️

... and 12 files with indirect coverage changes

Flag	Coverage Δ
integration-tests	16.69% <0.00%> (-0.02%)	⬇️
unit-tests	63.69% <66.66%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
reth binary	26.01% <ø> (ø)
blockchain tree	82.56% <ø> (ø)
pipeline	90.07% <ø> (ø)
storage (db)	74.73% <66.66%> (+<0.01%)	⬆️
trie	94.88% <ø> (ø)
txpool	47.23% <ø> (-0.50%)	⬇️
networking	77.66% <ø> (+0.15%)	⬆️
rpc	57.96% <ø> (-0.01%)	⬇️
consensus	63.53% <ø> (ø)
revm	31.89% <ø> (ø)
payload builder	6.78% <ø> (ø)
primitives	86.30% <ø> (ø)

[gakonst]

Do we have any insight on what the overhead looks like with more tables? Maybe negl?

[gakonst]

OK w merging this in the breaking-changes branch