WIP Connection pooler support

Add an initial support for a connection pooler. The idea is to make it
generic enough to be able to switch a corresponding docker image to
change from pgbouncer to e.g. odyssey. Operator needs to create a
deployment with pooler and a service for it to access.

pkg/util/constants/roles.go

@@ -2,15 +2,16 @@ package constants
 
 // Roles specific constants
 const (
-	PasswordLength         = 64
-	SuperuserKeyName       = "superuser"
-	ReplicationUserKeyName = "replication"
-	RoleFlagSuperuser      = "SUPERUSER"
-	RoleFlagInherit        = "INHERIT"
-	RoleFlagLogin          = "LOGIN"
-	RoleFlagNoLogin        = "NOLOGIN"
-	RoleFlagCreateRole     = "CREATEROLE"
-	RoleFlagCreateDB       = "CREATEDB"
-	RoleFlagReplication    = "REPLICATION"
-	RoleFlagByPassRLS      = "BYPASSRLS"
+	PasswordLength            = 64
+	SuperuserKeyName          = "superuser"
+	ConnectionPoolUserKeyName = "pooler"
+	ReplicationUserKeyName    = "replication"
+	RoleFlagSuperuser         = "SUPERUSER"
+	RoleFlagInherit           = "INHERIT"
+	RoleFlagLogin             = "LOGIN"
+	RoleFlagNoLogin           = "NOLOGIN"
+	RoleFlagCreateRole        = "CREATEROLE"
+	RoleFlagCreateDB          = "CREATEDB"
+	RoleFlagReplication       = "REPLICATION"
+	RoleFlagByPassRLS         = "BYPASSRLS"
 )