[Relay][Prelude] Use the Relay parser to define the Relay prelude (#3043)

[Relay][Prelude] Use the Relay parser to define the Relay prelude (#3043)

* Add ability to load Prelude from disk

* Port over id

* Define compose

* Linting errors and style changes

* Eliminate unnecessary parens

* Rename identType to typeIdent (makes more sense)

* Another unnecessary paren

* Bump the version number for the text format

* Ensure .rly (Relay text files) are permitted

* Correct release number and simplify grammar rule

* Correct load_prelude docstring

* Corrections to _parser

* Add Apache headers to prelude source file

* Remove test_prelude (redundant)

* Correct misleading error message

* Add check that parser is enabled in Prelude

* Commit pre-generated parser, ensure generated files are treated as binaries, and have parser tests always fire

* Permit parser files and git attributes files

* Exclude gitattributes and parser files from apache check

* Another attempt at appeasing Apache audit checker

* Corrections to rat-excludes

* Apache should be truly appeased now

* Ignore Relay parser files by name

* Mark parser files as generated so they don't show up on Github

* Add parsing helper function for tests

* Mark parser files as not detectable