Add a captcha for new users

[smyalygames]

Is your feature request related to a problem? Please describe.
To prevent bots from flooding the server

Describe the solution you'd like
When a user joins and agrees to the rules, they should be prompted to complete a captcha

Describe alternatives you've considered
Only requiring the user to agree to the rules, which would most likely need manual input from a user

[Leftyxiv]

Are you ok with adding more external dependencies? I know it can add to tech debt but this looks like it may be useful for this

https://www.npmjs.com/package/discord.js-captcha

[smyalygames]

Are you ok with adding more external dependencies? I know it can add to tech debt but this looks like it may be useful for this

https://www.npmjs.com/package/discord.js-captcha

This looks awesome! :D

I think this is something that may be added after we implement the verification system #35 and I could discuss how this should be done.