0.13.0 fixes around database quoting and rendering

[drewbanin]

• do not quote snowflake database identifiers by default (preserves <=0.12.2 behavior)
• do not find relations in source schemas in list_relations (strictly to speed up parsing -- is the mechanism shown here an acceptable way to accomplish this?)
• do not render database names in stdout if a custom database is not specified (aesthetics)

I took some liberties here to round out the rest of the feedback around the 0.13.0 prerelease, but happy to discuss or revisit any of these!

[beckjake]

Looks great! (edit: once the missing import is in/tests pass)

[drewbanin]

This is failing due to the changes required in #1326

By turning quoting off for databases on Snowflake, the catalog query now looks like:

         select *
            from tables
            join columns using ("table_database", "table_schema", "table_name")
            where "table_schema" != 'INFORMATION_SCHEMA'
              and "table_database" = DBT_TEST_ALT --- <---- this is not quoted
            order by "column_index"

So, let's fix 1326 then merge it in here