Add bar chart support to monitoring dashboard

What does this MR do?

This MR adds Bar charts to the monitoring dashboard. Bar charts was recently introduced in GitLab UI gitlab-ui!1136 (merged).

The original bar charts had an issue where long axis labels would overlap with y axis name. An update was made to the Bar charts (gitlab-ui!1199 (merged)) based on the conversation !27155 (comment 307126569)

Here !27173 (merged) is the MR to update docs.

Sample dashboard to test bar charts

dashboard: "Metrics Dev"
panel_groups:
  - group: "Operations group"
    panels:
      - type: bar
        title: "http response size incr by handler"
        x_label: 'Response Size'
        y_axis:
          name: "Handlers"
        metrics:
          - id: prometheus_http_response_size_bytes_bucket
            query_range: "sum(increase(prometheus_http_response_size_bytes_bucket[1d])) by (handler)"
            unit: 'Percent'

Screenshots

Bar chart with truncated labels
Bar charts among other charts

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Mentions #202000 (closed)