game: cleanup gk's CLI documentation (#2189)

An attempt to cleanup the last CLI interface we have left to cleanup. 
- `gk` args now follow the typical convention ie. `--proj-path` instead
of `-proj-path`.
- args that are passed through to the rest of the application / the
game's runtime use the typical convention of following a `--`
- I'm thinking some args shouldn't be handled at this level ie
(`-nodisplay`, `-vm`, `-novm` or `-jak2`) These could be better
documented as legitimate flags and passed in via a nice struct. They
don't seem to be used in `InitParams` but I'll triple check.

There's a temporary shim here so there is no coupled release with the
launcher (right now it executes `gk` with a few args). So I just change
the old args into the new format. After one release cycle, I can change
it in the launcher and delete it here.

I am unsure if this will break the bash shellscript usages -- not sure
which args were usually passed into `$@`


![image](https://user-images.githubusercontent.com/13153231/222035309-b6601719-cdc9-40ee-b36e-e4b135d3f128.png)

goalc/main.cpp

@@ -7,6 +7,7 @@
 #include "common/util/FileUtil.h"
 #include "common/util/diff.h"
 #include "common/util/string_util.h"
+#include "common/util/unicode_util.h"
 #include "common/versions.h"
 
 #include "goalc/compiler/Compiler.h"
@@ -24,6 +25,8 @@ void setup_logging() {
 }
 
 int main(int argc, char** argv) {
+  ArgumentGuard u8_guard(argc, argv);
+
   bool auto_find_user = false;
   std::string cmd = "";
   std::string username = "#f";