Add `register_database` method

[matthewmturner]

I would like to register a single database and not the entire glue catalog

[timvw]

The following functions are already available:

/// Register all tables in the given glue database
pub async fn register_tables(&mut self, database: &str) -> Result<Vec<Result<()>>> {

/// Register the table with the given database and table name
pub async fn register_table(&mut self, database: &str, table: &str) -> Result<()> {

[matthewmturner]

@timvw Ah sry I should have looked at the signatures closer. Thanks!

[timvw]

You're welcome ;)