Send the Discord spoiling code in attachment file

[pyrech]

Discord does not allow message to be more than 2000 chars. But with a lot of participants, the spoiling code can be quite long, so we could not send the admin message. Let now send the spoiling code in a attached file instead.

Also removed Restcord which is unmaintened and use symfony/http-client directly.

Here is how the admin message now looks:

In a future, we could also:

• do the same for slack?
• tweak the spoiling form to accept a file upload and avoid people to need to manually copy the code and just upload the file

[damienalexandre]

Great, thanks!

Maybe just one issue, restcord/restcord was dealing with rate limits from the API. With this implementation we will not have this capability, am I right?

[pyrech]

Good catch, I will try to use the RetryableHttpClient from symfony/http-client to handle those cases

[pyrech]

Should be good now, a RetryableHttpClient is now used so it should respect the retry strategy from Discord