feat(weave): add metrics table for tracking alert metrics

[gtarpenning]

wip

[wandbot-3000[bot]]

Preview this PR with FeatureBee: https://beta.wandb.ai/?betaVersion=2e95908f4a20c945a00f82736bf5a46e5e0716e0

[codecov-commenter]

Codecov Report

:x: Patch coverage is 27.37430% with 130 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
weave/trace_server/sqlite_trace_server.py	7.40%	50 Missing :warning:
...ve/trace_server/clickhouse_trace_server_batched.py	16.12%	26 Missing :warning:
...erver/alert_metrics/alert_metrics_query_builder.py	15.38%	22 Missing :warning:
weave/trace_server/alert_metrics/schema.py	25.00%	21 Missing :warning:
...erver/external_to_internal_trace_server_adapter.py	22.22%	7 Missing :warning:
...server_bindings/caching_middleware_trace_server.py	50.00%	2 Missing :warning:
.../trace_server_bindings/remote_http_trace_server.py	50.00%	2 Missing :warning:

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