Add navdrawer and first ui mockup

build.gradle

repeater-android/build.gradle

repeater-android/src/main/AndroidManifest.xml

...n/org/briarproject/repeater/activity/NavDrawerActivity.kt

...kotlin/org/briarproject/repeater/fragment/BaseFragment.kt

...in/org/briarproject/repeater/fragment/OverviewFragment.kt

...in/org/briarproject/repeater/fragment/UserListFragment.kt

repeater-android/src/main/res/anim/screen_new_in.xml

repeater-android/src/main/res/anim/screen_new_out.xml

repeater-android/src/main/res/anim/screen_old_in.xml

repeater-android/src/main/res/anim/screen_old_out.xml

repeater-android/src/main/res/anim/step_next_in.xml

repeater-android/src/main/res/anim/step_next_out.xml

repeater-android/src/main/res/anim/step_previous_in.xml

repeater-android/src/main/res/anim/step_previous_out.xml

repeater-android/src/main/res/animator/fade_in.xml

repeater-android/src/main/res/animator/fade_out.xml

...roid/src/main/res/drawable-v24/ic_launcher_foreground.xml

repeater-android/src/main/res/drawable/ic_add_white.xml

repeater-android/src/main/res/drawable/ic_contacts.xml