Move src/mobile into main repository (#864)

* Move `src/mobile` into main repository

* Update go.mod/go.sum

* Move to `contrib`, separate mobile build script

contrib/mobile/build

@@ -0,0 +1,52 @@
+#!/bin/sh
+
+set -ef
+
+[ ! -d contrib/mobile ] && (echo "Must run contrib/mobile/build.sh [-i] [-a] from the repository top level folder"; exit 1)
+
+PKGSRC=${PKGSRC:-github.com/yggdrasil-network/yggdrasil-go/src/version}
+PKGNAME=${PKGNAME:-$(sh contrib/semver/name.sh)}
+PKGVER=${PKGVER:-$(sh contrib/semver/version.sh --bare)}
+
+LDFLAGS="-X $PKGSRC.buildName=$PKGNAME -X $PKGSRC.buildVersion=$PKGVER"
+ARGS="-v"
+
+while getopts "aitc:l:d" option
+do
+  case "$option"
+  in
+  i) IOS=true;;
+  a) ANDROID=true;;
+  t) TABLES=true;;
+  c) GCFLAGS="$GCFLAGS $OPTARG";;
+  l) LDFLAGS="$LDFLAGS $OPTARG";;
+  d) ARGS="$ARGS -tags debug" DEBUG=true;;
+  esac
+done
+
+if [ -z $TABLES ] && [ -z $DEBUG ]; then
+  LDFLAGS="$LDFLAGS -s -w"
+fi
+
+if [ ! $IOS ] && [ ! $ANDROID ]; then 
+  echo "Must specify -a (Android), -i (iOS) or both"
+  exit 1
+fi
+
+if [ $IOS ]; then
+  echo "Building framework for iOS"
+  go get golang.org/x/mobile/bind
+  gomobile bind \
+    -target ios -tags mobile -o Yggdrasil.xcframework \
+    -ldflags="$LDFLAGS $STRIP" -gcflags="$GCFLAGS" \
+    ./contrib/mobile ./src/config;
+fi
+
+if [ $ANDROID ]; then
+  echo "Building aar for Android"
+  go get golang.org/x/mobile/bind
+  gomobile bind \
+    -target android -tags mobile -o yggdrasil.aar \
+    -ldflags="$LDFLAGS $STRIP" -gcflags="$GCFLAGS" \
+    ./contrib/mobile ./src/config;
+fi