Add automatic update checking service

build.gradle

java/AndroidManifest.xml

java/res/values/strings-uix.xml

java/src/org/futo/inputmethod/latin/LatinIME.kt

...src/org/futo/inputmethod/latin/uix/settings/pages/Home.kt

java/src/org/futo/inputmethod/updates/Update.kt

java/src/org/futo/inputmethod/updates/UpdateChecking.kt

...src/org/futo/inputmethod/updates/UpdateCheckingService.kt

java/src/org/futo/inputmethod/updates/UpdateResult.kt

tests/AndroidManifest.xml