Config based installed games localization

[UncleGoogle]

Is your feature request related to a problem? Please describe.
Only some games are automatically detected as installed on Windows based on registry. We need all.

Describe the solution you'd like
Add scanning folders feature that will perform batch matching based on root path provided in config file.

Or maybe list of root paths as general solution.

Use existing heuristics to find all games with executables.

Describe alternatives you've considered

• Manual matching games with minimal gui shown after clicking on install.
  It is sill an option but requires work on gui and not gives batch matching. Do later.

• Do not use config file but cache and chromium gui at last login step.
  Chromium gui would be nice as user dont have to manually change any file, but the window cannot be called on demand (well, maybe on reconnecting). It is definitely thing to do, but maybe as a next step altogether with other options and login window Alternative login method #15 Do it later.

• just use ProgramFiles / Applications as a root path for recursive search.
  May be heavy for CPU and the first try on Windows failed because of no read rights for whole filesystem. Sounds like a blocker but need to try on mac.

[UncleGoogle]

Windows done in #33. MacOS is tracked in this issue: #13.
I've decided to not add any default there, but open config.ini file after logging instead.