Update to get latest release from S3 (#15952)

* 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

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

Makefile

@@ -188,14 +188,9 @@ prepackaged-plugins: ## Populate the prepackaged-plugins directory
 
 prepackaged-binaries: ## Populate the prepackaged-binaries to the bin directory
 ifeq ($(shell test -f bin/mmctl && printf "yes"),yes)
-	@echo "mmctl already exists in bin/mmctl not downloading a new version."
+	@echo "MMCTL already exists in bin/mmctl not downloading a new version."
 else
-	@MMCTL_VERSION=$$(scripts/get_latest_release.sh mattermost/mmctl release-); if [ $$? -eq 0 ]; then \
-		scripts/download_mmctl_release.sh $$MMCTL_VERSION; \
-	else \
-		echo $$MMCTL_VERSION; \
-		exit 1; \
-	fi;
+	@scripts/download_mmctl_release.sh
 endif
 
 golangci-lint: ## Run golangci-lint on codebase