Remove ACRA

This was requested by developers who never wound up using it. It's not
really worth keeping around, since the play console gives us most of
what we need anyway.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

app/build.gradle

@@ -65,7 +65,6 @@ android {
 }
 
 ext {
-    acraVersion = '5.2.0-rc2'
     databindingVersion = '3.1.3'
     jsr305Version = '3.0.2'
     streamsupportVersion = '1.6.0'
@@ -86,7 +85,6 @@ dependencies {
     implementation "com.journeyapps:zxing-android-embedded:$zxingEmbeddedVersion"
     implementation "net.sourceforge.streamsupport:android-retrofuture:$streamsupportVersion"
     implementation "net.sourceforge.streamsupport:android-retrostreams:$streamsupportVersion"
-    implementation "ch.acra:acra-http:$acraVersion"
 }
 
 tasks.withType(JavaCompile) {