Add Milvus overview dashboard

[dkirov-dd]

What does this PR do?

Adds an overview dashboard for Milvus.
See here

Motivation

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged

[maycmlee]

Created DOCS-9875 for docs review.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.57%. Comparing base (18d32c1) to head (4097758).
Report is 1 commits behind head on master.

Additional details and impacted files

Flag	Coverage Δ
activemq	?
cassandra	?
hive	?
hivemq	?
hudi	?
ignite	?
jboss_wildfly	?
kafka	?
presto	?
solr	?

Flags with carried forward coverage won't be shown. Click here to find out more.

[neko-dd]

Some small suggestions but over LGTM