Support spaces in --datadir paths

[moizpgedge]

1. • Normalize --datadir input by replacing all \ sequences with actual spaces
2. • Assign cleaned path to pg_data before directory creation and downstream use
3. • Ensure initdb, SSL cert generation, pg_hba.conf copy, and pg_ctl all target the real filesystem path
4. • Prevent errors when users pass paths like /home/moiz/pgdir_test\ 6 on the CLI

[moizpgedge]

The fix now passes the data-directory exactly once—wrapped in quotes but without backslashes—so paths like “/data/foo bar” work naturally.
All shell interactions funnel paths through shlex.quote, removing our old hand-built escapes and closing the command-injection hole Codacy flagged.