Add Alertmanager configuration management
Add alertmanager-config unit
Add options for Alertmanager to use an external secret generated by the alertmanager-config
Add HA, persistent storage and PDB
Closes #1172
Edited by Cristian Manda
Add alertmanager-config unit
Add options for Alertmanager to use an external secret generated by the alertmanager-config
Add HA, persistent storage and PDB
Closes #1172