Add an option to fake user's location

[ameshkov]

Take a look at how it's done here: https://github.com/mcastillof/FakeTraveler

We can do pretty much the same on Android.

Here's how it can be done:

1. Provide an advanced setting that "mocks" user's location.
2. We should add a whole screen for this feature and put the detailed explanation on how to enable it.
3. We should either let the user choose the specific location OR just re-use the endpoint's location.

@denis9229 what do you think about it?

[TPS]

Equivalent request for AGa @ https://github.com/AdguardTeam/AdguardForAndroid/issues/1477

Is it possible to customize this per app or server via choosing a different VPN server (or search string like https://github.com/AdguardTeam/AdGuardVPNForAndroid/issues/252#issuecomment-1872502945?) on Exclusions tab (maybe rename tab?), instead of (solely?) global mock location, especially for those of us who keep GPS off?

Also see app suite @ https://github.com/warren-bank/Android-Mock-Location