improve spec compliance

[urkle]

Contains several changes to improve spec compliance.

• Allow Note blocks at the root schema sticky notes
• Add notes on table groups spec
• Add table group settings spec
• improve tests so they compare against the ron files in the out folder (set the ENV UPDATE_DBML_OUTPUT=1 to have the test suite update the ron files)
  • enable test running for the mysql/mssql/postgres importer files
• Add in double-quoted string in attributes
  • needed for the DB importer files as the index names get exported in double-quotes
• improved column type handling to support
  • schemas in the col_type (e.g. schemaB.my_enum when using a enum from another schema)
  • [] placement on unquoted type names (e.g. char[] or my_enum[])
  • [] placement after the quoted type name (e.g. "character varying"[])
  • mixed quoting with schema (e.g. "schemaB"."my_enum" or schemaB."my_enum" etc.)

[apskhem]

Hi @urkle, thank you so much for this huge contribution! The PR has included the part that I'm going to address about that parsing weirdness of raw string, and also some additional improvements according to the spec. I think everything that you've done is pretty much okay. And I'm thinking that after merging your PR into the main branch, I'll change the version into stable 1.0.0 as you've include the test part and spec stabilization.

Thank you again. Big kudos to you 👏.