Add data directories paths in settings

@otkstdio, could we please put the paths to Bitcoin Core, Specter and maybe log file into the app settings. Imho it's good practice that users can find these locations without problems, and that also creates confidence when the user knows where the Bitcoin & Specter files are stored, and he can look at it.


Start by locating the app settings UI and the existing handling of Bitcoin Core, Specter, and log-file paths. Confirm which paths are available to display and how settings are presented. Done means users can find the relevant data directories and log-file location in the app settings.

Written by the indexing model from the issue text.