feat: add query_cache_parse_time metric

[levkk]

refactor: move pool stats into their own crate for reusability
refactor: move postgres data types to their own crate for reusability

[codecov]

Codecov Report

❌ Patch coverage is 81.33993% with 415 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
pgdog-postgres-types/src/numeric.rs	84.71%	98 Missing ⚠️
pgdog-postgres-types/src/datum.rs	35.00%	91 Missing ⚠️
pgdog-postgres-types/src/interval.rs	66.36%	37 Missing ⚠️
pgdog-postgres-types/src/array.rs	0.00%	32 Missing ⚠️
pgdog-postgres-types/src/timestamp.rs	95.13%	23 Missing ⚠️
pgdog-postgres-types/src/vector.rs	77.52%	20 Missing ⚠️
pgdog-postgres-types/src/boolean.rs	37.50%	15 Missing ⚠️
pgdog-postgres-types/src/double.rs	91.71%	14 Missing ⚠️
pgdog-postgres-types/src/uuid.rs	0.00%	14 Missing ⚠️
pgdog-postgres-types/src/interface.rs	71.05%	11 Missing ⚠️
... and 10 more

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