update gitignore and add gradle wrapper

.gitignore

@@ -1,13 +1,5 @@
-### Android ###
 # Built application files
 *.apk
-*.ap_
-
-# Files for the ART/Dalvik VM
-*.dex
-
-# Java class files
-*.class
 
 # Generated files
 bin/
@@ -17,62 +9,10 @@ out/
 # Gradle files
 .gradle/
 build/
-gradle/
-gradlew.bat
-gradlew
 
 # Local configuration file (sdk path, etc)
 local.properties
 
-# Proguard folder generated by Eclipse
-proguard/
-
-# Log Files
-*.log
-
-# Android Studio Navigation editor temp files
-.navigation/
-
-# Android Studio captures folder
-captures/
-
 # Intellij
 *.iml
 .idea/
-
-# External native build folder generated in Android Studio 2.2 and later
-.externalNativeBuild
-
-# Freeline
-freeline.py
-freeline/
-freeline_project_description.json
-
-### Android Patch ###
-gen-external-apklibs
-
-### fastlane ###
-# fastlane - A streamlined workflow tool for Cocoa deployment
-#
-# It is recommended to not store the screenshots in the git repo. Instead, use fastlane to re-generate the
-# screenshots whenever they are needed.
-# For more information about the recommended setup visit:
-# https://docs.fastlane.tools/best-practices/source-control/#source-control
-
-# fastlane specific
-fastlane/report.xml
-
-# deliver temporary files
-fastlane/Preview.html
-
-# snapshot generated screenshots
-fastlane/screenshots/**/*.png
-fastlane/screenshots/screenshots.html
-
-# scan temporary files
-fastlane/test_output
-
-# Google Play files
-fastlane/metadata/
-
-Gemfile.lock