Configuration of LMDB map size in other DBs than Baser

[rodolfomiranda]

Feature request description/rationale

In PR #810, @pfeairheller added a feature to set the maximum file size for the main KERIpy LMDB database (Baser).
In witnesses, we realized that also the mailbox DB can grow considerably, so we need a way to change the map_size config for other dbs.
Should we allow the configuration on some selected DBs? or should we apply a global setting in LMDBer? I'd like to hear opinions before starting a PR.

[SmithSamuelM]

I suggest that adding parameters to LMDBer.reopen to override the default settings for maxdbs and maxsize will work for all instances. then fix config to provide those overrides when setting up dbs.