Add per db metrics (#4183)

* Add per-db metrics to OTel

This PR adds changes to allow per-db metrics in OTel:

- change API for per-db metrics
- add default metrics for per-db metrics based on pgmonitor 5.2.1
- remove unused metrics
- add kuttl test

Author: benjaminjb

config/crd/bases/postgres-operator.crunchydata.com_pgadmins.yaml

@@ -2120,6 +2120,13 @@ spec:
                                   type: string
                                   x-kubernetes-validations:
                                   - rule: duration("0") <= self && self <= duration("60m")
+                                databases:
+                                  description: |-
+                                    The databases to target with added custom queries.
+                                    Default behavior is to target `postgres`.
+                                  items:
+                                    type: string
+                                  type: array
                                 name:
                                   description: |-
                                     The name of this batch of queries, which will be used in naming the OTel
@@ -2165,6 +2172,12 @@ spec:
                               type: string
                             type: array
                         type: object
+                      perDBMetricTargets:
+                        description: User defined databases to target for default
+                          per-db metrics
+                        items:
+                          type: string
+                        type: array
                     type: object
                   resources:
                     description: Resources holds the resource requirements for the

config/crd/bases/postgres-operator.crunchydata.com_postgresclusters.yaml

@@ -11965,6 +11965,13 @@ spec:
                                   type: string
                                   x-kubernetes-validations:
                                   - rule: duration("0") <= self && self <= duration("60m")
+                                databases:
+                                  description: |-
+                                    The databases to target with added custom queries.
+                                    Default behavior is to target `postgres`.
+                                  items:
+                                    type: string
+                                  type: array
                                 name:
                                   description: |-
                                     The name of this batch of queries, which will be used in naming the OTel
@@ -12010,6 +12017,12 @@ spec:
                               type: string
                             type: array
                         type: object
+                      perDBMetricTargets:
+                        description: User defined databases to target for default
+                          per-db metrics
+                        items:
+                          type: string
+                        type: array
                     type: object
                   resources:
                     description: Resources holds the resource requirements for the