Added repopick from LOS

Credit to mikeNG <mkbestas@lineageos.org>
This commit was not cherry-picked because there was too many
unrelated changes in the original commit.

Change-Id: Ie6b13ae0b9d2bf31395c14f0eda8a78d5fa417f8
diff --git a/build/envsetup.sh b/build/envsetup.sh
index 3060c8d..9ed3341 100644
--- a/build/envsetup.sh
+++ b/build/envsetup.sh
@@ -244,6 +244,11 @@
 
 alias bib=breakfast
 
+function repopick() {
+    T=$(gettop)
+    $T/vendor/bliss/build/tools/repopick.py $@
+}
+
 function fixup_common_out_dir() {
     common_out_dir=$(get_build_var OUT_DIR)/target/common
     target_device=$(get_build_var TARGET_DEVICE)