Simple pgpass parser

As the comment says, it should probably use something better for
error reporting than attoparsec because you'd actually expect to
see errors you want to report to the user here.

Also the return type of readPgPass is kind of icky, but I like the
separation of filesystem related errors vs. file content related
errors.  It probably won't stay this way though.
Allow recompile-all to be used before the connection pkgs are registered