feat(Songsterr): Remove ads from Songsterr/add more/custom tunings for bass and guitar

[bybrl]

Feature description

I would like to have ads removed from Songsterr, have the ability to search for tabs with a custom tuning and search for tabs by artists.
com.songsterr

Motivation

Ads on Songsterr are very intrusive. They will appear as you click a tab and click off a tab. Some songs, such as Never Meant by American Football and Mayonaise by The Smashing Pumpkins have tunings that are outside of the regular drop, standard, and open tunings. I believe that these changes would benefit the app and its users.

Acknowledgements

• I have checked all open and closed feature requests and this is not a duplicate
• I have chosen an appropriate title.
• All requested information has been provided properly.