fix h2

decide if h2 has to have a container on its own or not.

if it has it , it's more symetric with others.
We have to take into account that 'sharing' networks might imply duplicated h2 containers if we default to :h2.

cant start server caus it locks the db file

No file, test, or entry point is named. Start by locating the H2 configuration and reproducing the database-lock failure when the server starts, then assess the effect of defaulting to :h2 on shared networks. Done means the container decision is explicit and the server no longer fails because the database file is locked.

Written by the indexing model from the issue text.