DBMON-4720: Make all sql server database metrics configurable

[azhou-datadog]

What does this PR do?

1. Make collection of all database metrics for sql server configurable
2. Restructure database metrics in configuration file so related configurations are nested and visually grouped. This also consolidates setting the default database metric configurations in a single file, config.py, rather than spread throughout the codebase.
3. Deprecates usage of instance_config in favor of SQLServerConfig in database_metrics.

Motivation

Allowing database metrics collection to be individually configurable allows support to identify and triage performance issues related to metric collection. The new structure also is more extensible in the future, it is now easy to add related metric collection configurations.
Prevent passing instance_config unnecessarily down to SqlserverDatabaseMetricsBase objects, when it can all be handled in the initial configuration of SQLServerConfig.

OLD CONFIGURATION STRUCTURE
include_xyz_metric : True
include_foo_metric: False
include_xyz_metric_tempdb: False
include_xyz_metric_interval: 300
etc...

NEW CONFIGURATION STRUCTURE
database_metrics
 xyz_metric
  enabled: True
  interval: 300
  enabled_tempdb: False
 foo_metric
  enabled: False
etc...

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

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[codecov]

Codecov Report

Attention: Patch coverage is 98.35165% with 3 lines in your changes missing coverage. Please review.

Project coverage is 87.36%. Comparing base (6bbd75f) to head (fbd2497).
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	?
nvidia_nim	?
presto	?
solr	?
sqlserver	91.16% <98.35%> (+9.27%)	⬆️

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