Docker: remove intervals and timeouts

These weren't needed at all and provided false negatives in
general. Removed them to let Docker deal with them.

Additionally. 'exit 0' -> 'echo' for ca's command; 'exit 0'
happens to depend on the shell running Docker (it seems).
echo is quite a bit more agnostic.

Moreso, added mariadb deps to php-fpm and fastapi.

Signed-off-by: Kevin Morris <kevr@0cost.org>