Pass multiple filenames and --inplace to pgFormatter

[grantcox]

pgFormatter supports passing multiple filenames, and the --inplace argument to update these directly. With these two changes, we can process many files in each pgFormatter execution, which is somewhat faster:

When using my local project with 480 SQL files (approx 1.1MB total)

• The current "one at a time" takes 38 seconds
• Doing in chunks of 10 takes 19.2 seconds
• Doing in chunks of 25 (default in this PR) takes 17.8 seconds
• Doing in chunks of 100 takes 17.3 seconds

[bradymholt]

Thanks @grantcox - looks great 👍