[Telemetry Audit] Break down our massive metrics.yaml file into separate component-specific metrics YAML files

[data-sync-user]

Currently, our metrics.yaml file is well over 6,000 lines long.

We can break down our large metrics file into multiple smaller metrics files specific to our larger components. This will make it easier to find and adjust probes for specific purposes.

Tags may also be applied at the file level:

Glean reference: https://mozilla.github.io/glean/book/reference/yaml/metrics.html#tags

If possible, investigate ways to enforce alphabetized probe namespaces as well in each metrics file.

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