src: Move all source code to src/newlang ...

The Python ecosystem works much better if we deicide our source code
is actually a module named 'newlang'.

I've been putting off changing this for a long time, but I might as
well do it now.

parse: Rename oldparse back to parse ...

This is the primary actually working parser, not an old one.

parse2: Move all new parser code to the parse2 namespace ...

This is a bit of a messy mass rename but it seems to work and makes things
clearer in preparation for a new parse module.

This also renames the NEWLANG_NEW_PARSE test environment variable to
NEWLANG_PARSE2.

tests: Add more test_note documentation

tests: Add more clear_notes documentation

parse: Take parse_file out of Parser wrapper

parse: Drop NoteSkipper wrapper class

tests: Fix invalid directive comments

tests: Check clear_notes error passthrough

tests: Replace file parsing mock with static directives

tests: Simplify clear_notes tests ...

This replaces mocking static tests and assumes errors are parsed
through because the actual parser is triggered.

tests: Wrap test_oldparse's draw_token_empty in just

tests: Remove unused template_parse_* functions

tests: Don't return old tokens in draw_token_statement_invalid_value

tests: Fix draw_token_statement_invalid_value overwriting terminator

tests: Refactor test_statement to use template_test_*

tests: Remove unused template_parse_valid and template_parse_invalid

tests: Refactor test_value to use template_test_*

tests: Remove unused insert_random_within

tests: Refactor test_reference to use template_test_*

tests: Fix typo in test_note

tests: Refactor test_text to use template_test_*

tests: Refactor test_clear_notes to use template_test_*

tests: Refactor test_note to use template_test_*

tests: Refactor test_bool to use template_test_*

tests: Expect arrays for messages instead of dicts

parse: Drop enum class in favor of DIY method ...

This is slightly sketchy but should be enough to get MicroPython working
with the new parser.

tests: Minor whitespace fix

parse: Create messages from ParseTasks

parse: Add filename to error messages