Convert CSV column names into ASTs without parsing them

[georgesittas]

Context: #2634

Seed models that contain columns with special characters in them are currently not handled properly. It seems like we're trying to parse the CSV column names using maybe_parse at some point during loading, which can cause a ParseError instead of converting the "unsafe" identifiers into quoted columns.

This can be demonstrated using the example project, by simply renaming event_date to event_date. in the CSV file. This is the error we currently get:

sqlglot.errors.ParseError: Required keyword: 'this' missing for <class 'sqlglot.expressions.Column'>. Line 1, Col: 11.
  event_date.

To fix this, my guess is that we should use to_identifier or something similar, to ensure we'll simply produce a quoted identifier instead of crashing.