Increase Gradle HTTP timeouts from 30 => 120 seconds

Problem: Gradle's default 30 second HTTP timeouts often cause bisq-*
component builds to fail when resolving dependencies built on the fly
via JitPack, e.g.:
https://travis-ci.org/bisq-network/bisq-core/builds/356777615#L518-L525.

Solution: Increase timeout values to 120 seconds, which should be more
that sufficient.

See:
 - gradle/gradle#3370
 - gradle/gradle#3371
 - gradle/gradle#4629

gradle.properties

@@ -0,0 +1,2 @@
+systemProp.org.gradle.internal.http.connectionTimeout=120000
+systemProp.org.gradle.internal.http.socketTimeout=120000