MMCTL download migration to S3 location (#15993)

* Update to get latest release from S3

* Update mmctl to download to use S3

* Download MMCTL from S3

* Update download_mmctl_release.sh

* Update Makefile

* Update release.mk

* Update the script called, remove call to sub shell and clean up indentation

* Add quotes around THIS_BRANCH var

* Update script to support overriding the OS for packaging

* Add check for release-<Digit> to better match the branch

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

scripts/download_mmctl_release.sh

@@ -15,7 +15,7 @@ fi
 
 # strip whitespace
 THIS_BRANCH=$(git rev-parse --abbrev-ref HEAD)
-if [[ "$THIS_BRANCH" =~ 'release-' ]];
+if [[ "$THIS_BRANCH" =~ 'release-'[0-9] ]];
 then
   RELEASE_TO_DOWNLOAD="$THIS_BRANCH"
 else