[Metricbeat] Add PostgreSQL Dashboard

[sorantis]

Partially addresses #10594.
Closes: #13103.

The dashboards shows the following metrics:

- name: database
  - name: transactions.commit
    description: Number of transactions in this database that have been committed.
  - name: transactions.rollback
    description: Number of transactions in this database that have been rolled back.

  - name: blocks.time.read.ms
    description: Time spent reading data file blocks by backends in this database, in milliseconds.
  - name: blocks.time.write.ms
    description: Time spent writing data file blocks by backends in this database, in milliseconds.

  - name: rows.returned
    description: Number of rows returned by queries in this database.
  - name: rows.fetched
    description: Number of rows fetched by queries in this database.

  - name: rows.inserted
    description: Number of rows inserted by queries in this database.
  - name: rows.updated
    description: Number of rows updated by queries in this database.
  - name: rows.deleted
    description: Number of rows deleted by queries in this database.

  - name: conflicts
    description: Number of queries canceled due to conflicts with recovery in this database.
  - name: deadlocks
    description: Number of deadlocks detected in this database.

- name: statement
  - name: query.calls
    description: Number of times the query has been run.

  - name: query.time.total.ms
    description: Total number of milliseconds spent running query.

  - name: query.memory.shared.hit
    description: Total number of shared block cache hits by the query.
  - name: query.memory.shared.read
    description: Total number of shared block cache read by the query.

  - name: query.memory.local.hit
    description: Total number of local block cache hits by the query.
  - name: query.memory.local.read
    description: Total number of local block cache read by the query.

[sorantis]

jenkins, test this please

[kaiyan-sheng]

Sorry one more thing, if you click edit dashboard, then you can see Customize panel:

Then you can remove the [Metricbeat PostgreSQL] part from visualization titles just for the dashboard.

[sorantis]

fixed