Adds luau.requires to @std

[tyulpan]

Adds luau.requires(filePath: path.pathlike): { RequireNode } to @std, which parses Luau source code and returns all of its required modules in the following format:

{
  resolvedPath: string?, -- the path to the resolved require
  requireContent: string?,  -- an argument passed to the require as a string literal
  requireAst: luteLuau.AstExprCall, -- the ast expression passed to require
}

Resolves #776.
Related to PR #878.

Now we can run this code for hash.luau:

local pp = require("@batteries/pp")
local luau = require("@std/luau")

local requires = luau.requires("./examples/hash.luau")

print(pp(requires))

and get:

{
  {
    requireContent = "@lute/crypto",
    resolvedPath = "/path/to/lute/definitions/crypto.luau",
    requireAst = {...}
  },
  {
    requireContent = "@batteries/base64",
    resolvedPath = "/path/to/lute/batteries/base64.luau",
    requireAst = {...}
  },
}