Write guide "Set up LDAP authentication for The Lounge"

[xPaw]

Would live at http://thelounge.chat/docs/guides/ldap

[astorije]

Hey @gramakri, do you think you could help us with that? You don't have to write the full thing, but if you had bullet points or anything to help me write it, that'd be super helpful. Happy to write it with you.

[gramakri]

Yup, I can write a doc. I should submit a PR to this directory https://github.com/thelounge/thelounge.github.io/tree/master/_guides correct?

[xPaw]

Yes.

[astorije]

@gramakri, correct, I've set up a placeholder at https://github.com/thelounge/thelounge.github.io/blob/astorije/ldap/_guides/ldap.md (result at https://astorije-ldap--thelounge.netlify.com/docs/guides/ldap), feel free to open a PR against my branch astorije/ldap (then I can squash my commit into your stuff).

In case you can't run Jekyll on your end, simply open a PR and there will be a deploy preview (when Netlify fixes them :D).

[gramakri]

Sorry for the delay, I made a PR now.