Added configurable TTL for heartbeat

Ported from commit: https://github.com/Particular/ServiceControl.Plugins.v4/commit/f2aaf75c6ea037fba9a9fb53d7b5ae9b78177189#diff-d02339b581837bd3a0ad43d54a710978R35
Also made the RegisterEndpointStartup message expire by the same TTL.
Cleanup project structure
Adjusted the namespace
Added the .yaml file to fix the asm to just Major
Merge branch 'release-1.1.0'