MT#57982 Do not install redis-server anymore

We only support keydb now, so we should not be installing the redis
server anymore. We add explicit dependencies on redis-tools as those
work against keydb servers too, for a smooth transition, while admins
train their muscle memory with keydb-tools.

Change-Id: I17742249462f069cb57b786884aa234765350774

debian/control

@@ -383,7 +383,7 @@ Depends:
  prometheus-node-exporter,
  prometheus-process-exporter,
  prometheus-redis-exporter,
- redis-server,
+ redis-tools,
  rsyslog,
  slapd,
  smartmontools,
@@ -489,7 +489,7 @@ Depends:
  prometheus-node-exporter,
  prometheus-process-exporter,
  prometheus-redis-exporter,
- redis-server,
+ redis-tools,
  rsyslog,
  smartmontools,
  ssh,