Add option to disabling filtering for supported nodes only in the Android app

[soffokl]

By default, we are filtering unsupported nodes automatically.
But there should be an option to disable this filtering if a user wants it.
Users should be able to enable/disable in config such auto-detection.

This PR adds const to set NAT compatibility to auto #446
Passing an empty string instead of auto will disable this filter.

[cvl]

Is there any specific use case why would anyone want to disable NAT compatibility auto-detection?

[soffokl]

@cvl
If you are node running you probably want to be able to see your node in the list even if this is not compotible with a current NAT Type.

[cvl]

Thanks.

Additionally I can see in mysteriumnetwork/mysterium-vpn-desktop#184 that having this auto-detection enabled adds several seconds to load proposals list.

[soffokl]

This was a part of the discussion, it will not be adding such deley.

[tadaskay]

UI from desktop for this setting that you can use as a reference

[ArtemHryhorovGeniusee]

Implemented here:
#455