Build: Add CloudMode to build versions (#65651)
* Add CloudMode to build versions
* Use linux-amd64 variant without musl for cloud mode
* Add cloud mode to version folder on package upload
* Use musl variant for CloudMode
* Only sign rpm packages if there's any to sign
* Remove trailing whitespace
(cherry picked from commit 8f282b8a6e)
Co-authored-by: Guilherme Caulada <guilherme.caulada@grafana.com>