stdlib: Introduce a small standard library utility for writing tests …

…in lute (#393)

Based on [frktest](https://github.com/itsfrank/frktest)

This testing utility needs a bunch of assertions to be more useful, but
this PR just scopes out what a simple, builtin testing api in Luau could
look like.

For some tests that look like:
```
local test = require("@std/test")
local check = test.assert
test.case("foo", function()
	   check.eq(3, 3)
	   check.eq(6, 1)
end)

test.case("bar", function()
	   
	   check.eq("a", "b")
end)

test.case("baz", function()
	   
	   check.neq("a", "b")
end)

test.suite("MySuite", function()
	test.case("subcase", function()
		check.eq(5 * 5, 3)
	end)
end)

test.run();
```

this will render as:
```
❯ ./build/xcode/debug/lute/cli/lute run examples/testing.luau

==================================================
TEST RESULTS
==================================================

Failed Tests (3):

❌ foo
   ./examples/testing.luau:5
        eq: 6 ~= 1

❌ bar
   ./examples/testing.luau:10
        eq: a ~= b

❌ MySuite.subcase
   ./examples/testing.luau:20
        eq: 25 ~= 3

--------------------------------------------------
Total:  4
Passed: 1 ✓
Failed: 3 ✗
==================================================
```
Currently reports:
- [x] Test suites and cases
- [x] Line numbers
- [x] Stack traces
- [x] The expression that failed.

Create lute --version command (#390)

Update the bootstrap script to actually build two copies of lute (#386)

The bootstrap script didn't correctly generate the lute standard library
headers that the `luthier` script did. This PR:
- generates a minimal header and implementation for the lute standard
libraries during the bootstrap phase
- uses these headers to build a `bootstrapped-lute` binary
- uses that `bootstrapped-lute` to run `luthier.luau` which builds the
actual `lute` executable with the `std` library correctly generated.
- accepts an `--install` argument to install this `lute` binary to
`$HOME/.lute/bin`.

There are some additional improvements that have been made:
1. General README fixes
2. This script can now be run multiple times in sequence, and it
correctly deletes artifacts generated by the bootstrapping process each
time (e.g. generated std headers, dependencies).
3. Uses git commands to `clone` only the particular revision of the
`extern` dependencies we care about, not the entire history.

---------

Co-authored-by: ariel <aweiss@hey.com>

infra: copy compile_commands to `build/` in the configure step (#387)

Fixes #348 by copying `compile_commands.json` to
`build/compile_commands.json` during the configure step.

Manually get the full body including any \0 instead of relying on the…

… string length (#379)

Without this we would get a truncated body and curl would hang waiting
for the missing bytes to send.

Test:

```luau
local net = require("@lute/net")
local pp = require("@batteries/pp")

local function test(payload: string)
	local response = net.request("https://httpbin.org/post", {
		method = "POST",
		headers = {
			["Content-Type"] = "application/octet-stream",
		},
		body = payload,
	})
	print(response.status, pp(response.headers), response.ok, pp(response.body))
end

test("Hello World") -- works
test("Hello\0World") -- hangs
```

`Content-Length` is 11 for both.

Implement task.delay (#372)

This PR implements task.delay in the form of `<T..., U...>(dur: number |
time.Duration, routine: (T...) -> U..., ...: T...)`.

`yieldLuaStateFor` was also changed to accept an `nargs` parameter, to
support using that function for `task.delay`.

Closes #260

---------

Co-authored-by: ariel <aweiss@hey.com>

Add printType function (#377)

Allow required modules to return string and numeric values (#373)

Based on this PR in the Luau repository:
luau-lang/luau#1967.

I also spent a while trying to get newlines in error messages to play
nicely, but we still have some issues that we'll need to address later.
Main tension is that `lua_debugtrace` automatically puts a newline at
the end of the trace, but a "regular" error on a thread is usually just
a string with no newline.

RequireVfs: Remove all `default` blocks in favor of being explicit (#371

)

When first implementing this, I didn't realize that the compiler checks
for exhaustivity when switching over an enum. This is an improvement
that helps us catch errors at compile-time by being more explicit.

Add printStatement func to printer (#361)

There are print cases not covered by `printBlock` and `printExpr`, so I
figure this is useful to have

If anything, we can replace `printBlock` with this function and export
it as `print` instead, [since`visitStatement` encompasses
blocks](https://github.com/luau-lang/lute/blob/primary/lute/std/libs/syntax/visitor.luau#L796),
in addition to many statement types

---------

Co-authored-by: ariel <aweiss@hey.com>