Adding in redis cluster management

This version adds command line flags and an environment variable to enable using Redis to manage members of the samproxy cluster.

CI tweaks

No change to samproxy, just changing build configs.

Additional packaging formats

Adding .deb and .rpm to the artifacts generated as part of a release.

Initial versioned release

This is the first release of samproxy to have an artifact published back to github with a fixed version.

Changes since the last "release" (aka head of master before this version) is the addition of the option to use Redis to handle managing the list of online peers within the samproxy cluster.

This release is still beta; expect more to come.