Update Lua module methods to never return errors

[rkusa]

We had issues with a crash from an error returned by the dcs_grpc.dll in the past, see #19. We fixed that by directly logging the offending error instead of returning it to Lua, see bd54607.

I've investigated this again. I tried to reproduce this issue outside of DCS (basically with a lua.exe and a minimal Lua module written in Rust using mlua), but was unsuccessful - I couldn't reproduce it outside of DCS. As I don't have any idea left of how to fix/narrow down this issue, I give up and and would suggest to avoid returning errors from Rust to Lua entirely. This is also what this PR changes. It ensures that all calls to grpc.* methods never error. If they encounter an error internally, the error is logged right away and not returned to Lua first.

Drawback: The errors will not land in the Logs/dcs.log file and instead only in Logs/gRPC.log

Potentially fixes the crash reported by the Enigma server admins (see https://discord.com/channels/696721363276267590/962651858760003594/977730972206366781).
Fixes #138

[rurounijones]

Nitpick. Could we expand on this where we mention that all errors are now logged only to grpc.log

[rurounijones]

Just saw in related comment that this only happens in hot-loading. In that case I am fine to continue returning errors to lua and maybe we just document this as a known issue if you are using hot_loading (which no production server should be using as far as I am concerned).

[rkusa]

On hold for now, see #138 (comment)

[rurounijones]

Closing as no longer needed.

[rkusa]

For the record, we closed this PR as we've only ever reproduced it while using the development hot-reload functionality and figured, as it doesn't happen for normal installations, that for now, it wasn't worth the drawback of the error logs only appearing in Logs/gRPC.log.

[rkusa]

Fixed with #188