Seeing if we can reduce Berkeley DB usage.

For Python, most Linux distros just use gdbm rather than BDB, but Homebrew has a harder time directly linking to GPL dependencies as we cannot rely on GNU's "system library" exception.

Approach here would be making dependents that need dbm.ndbm support add:

on_linux do
  depends_on "python-gdbm@3.14"
end

Also, since Python 3.13, dbm provides dbm.sqlite3 so there is at least some functionality available without python-gdbm installed. So I expect lifespan of berkeley-db@5 to be aligned to deprecation date of either Python 3.12 (2028-10) or 3.13 (2029-10) depending on whether we backport to Python 3.13.

python-gdbm@3.14 is revision bumped to avoid missing _dbm in case python@3.14 is reinstalled but not python-gdbm@3.14.

python@3.14 does not need a revision bump as modules are installed in non-conflicting directories. If both _dbm exist, original would be loaded first and should work as expected.