[Go] support auth methods beyond access tokens

[amoeba]

Databricks and the underlying Go SQL driver support three auth methods,

• PAT
• OAuth U2M
• OAuth M2M

https://docs.databricks.com/aws/en/dev-tools/go-sql-driver#authentication

The driver only supports access tokens right now,

databricks/go/database.go

Lines 98 to 104 in 759b66b

	// FIXME: Support other auth methods
	if d.accessToken == "" {
	return nil, adbc.Error{
	Code: adbc.StatusInvalidArgument,
	Msg: "access token is required",
	}
	}