Improve interactive client management with loops and cancel options, …

[haashimhash]

Improve interactive client management with loops and cancel options and standardize client configuration directory just in home to wg subdirectory.

Key changes:

1. The manageMenu function is now wrapped in a while true loop, keeping the script alive until the user explicitly selects option 5 (Exit) or selects 4 (uninstall wg).
2. Replaced hard exit 1 calls with return 1 in sub-functions (newClient, listClients) and placed revokeClient on while loop to make revoking user easily as it now stays until broke when selected 0 to go back to main menu.
3. Added a "Press any key to continue..." prompt after any action is completed. This pause gives the user time to read the command output (e.g., the client list or a success message) before the menu clears and refreshes.
4. Pointed client conf files towards a 'wg' folder instead of flooding user dir.