Add useful links to features and types in features and types templates

[amoeba]

The current features and types tables list things without linking to a place that could give the user more information.

For example, "Bulk Ingestion" could be a URL to more info on ADBC bulk ingestion:

And BIGINT and int64 could be links to where those types are documented:

I think a pretty reasonable way to do this would be to,

1. For Arrow features and types, encode these in the validation suite codebase itself
2. For database-specific stuff, add tags in the validation tests in each driver repo. That way the knowledge about the database stays with the driver.

I think (2) makes sense because we currently store the sql-type-name in the validation suite like this,

https://github.com/adbc-drivers/mysql/blob/3e1e86db2ddfe1ca1f81542d6b98eed15859c669/go/validation/queries/type/select/json.toml#L15-L16

json.toml:

[tags]
sql-type-name = "JSON"

which could be

[tags]
sql-type-name = "JSON"
sql-type-url = "http://example.com"

We could give guidance to driver builders to consider this when building out their tests.

[lidavidm]

Makes sense. #58, #77 would also be nice as we start adding more flexibility