feat: Add support for Redshift-Serverless

[nickbazinet]

Add support for scraping Redshift-Serverless metrics.

When I queried the /metrics endpoint, I was able to view the expected metrics:

This is my first PR on this project and I am not 100% sure about the ResourceFilters in services.go, but based on my understanding it seems proper.
Feedback is then appreciated :)

This was based on this config:

 jobs:
  - type: AWS/Redshift-Serverless
    regions: *regions
    roles: *masterArns
    enableMetricData: true
    metrics:
      - name: DatabaseConnections
        statistics:
          - Average
        period: 60
        length: 60
        nilToZero: true
      - name: ComputeCapacity
        statistics:
          - Average
        period: 60
        length: 60
        nilToZero: true
      - name: QueriesCompletedPerSecond
        statistics:
          - Average
        period: 60
        length: 60
        nilToZero: true
      - name: ComputeSeconds
        statistics:
          - Average
        period: 60
        length: 60
        nilToZero: true
      - name: QueriesFailed
        statistics:
          - Average
        period: 60
        length: 60
        nilToZero: true
      - name: QueriesQueued
        statistics:
          - Average
        period: 60
        length: 60
        nilToZero: true
      - name: QueriesRunning
        statistics:
          - Average
        period: 60
        length: 60
        nilToZero: true
      - name: QueriesSucceeded
        statistics:
          - Average
        period: 60
        length: 60
        nilToZero: true
    exportedTagsOnMetrics: *masterTags