Add embed functionality

[ghost]

It would be very useful if there were functionality that lets you embed files into your program, similar to Go's use of it with //go:embed, or Nim's os.slurp()(staticRead), and then allows you to access the file as if it were in the same directory as the Odin program.

It could possibly be something like @(embed="file.txt") above a const variable, embedding the given file, file.txt into the variable.

[Kelimion]

#load(filename) will embed a file and make it available as a []u8 constant.

[ghost]

Oh, nice. Do I have to import anything to use it? Where's the documentation for it? I couldn't find anything relating to embedding files.

[Kelimion]

Nothing to import. It's a directive. Good idea to add it to the docs.

There's 3 related ones:
#load(filename) returns a constant slice of bytes, the file contents.
#load_or(filename) or alternative_constant returns a constant slice of bytes, the file contents, or another []byte constant if the file wasn't present.
#load_hash(filename, algorithm) returns a compile-time constant hash of the file.