MozStumbler v0.12.0

Special shout-out to @tamcap, our busiest contributor for this release! :cake:

* Add "Upload only on Wi-Fi" option (@tamcap)
* Refactor reporter to reduce memory usage (@cpeterso)
* Cleaning up the error output of MainActivity.java (@tamcap)
* Add Poland Koleje Slaskie train to SSID blocklist (@tamcap)
* Add BlackBerry OS to SSID blocklist (@SunboX)
* Update Simplified Chinese translation (@l-hedgehog)
* Update French translation (@pl6025)
* Update Spanish translation (@stripTM and @rodmoreno)
* Update Russian translation (@CupIvan)
* Update Polish translation (@tamcap)