Add no-multiple-empty-lines

[gabro]

Issue #80 (partially)

Test plan

Linto 🎉

	repo	errors	warnings
✅	buildo/aliniq	0	0
✅	buildo/web-shared	0	0
✅	buildo/lexdoit	0	0
✅	buildo/ipercron	0	0
✅	buildo/bobafett	0	0
✅	buildo/avenger	0	0
✅	buildo/react-components	0	0
✅	buildo/rc-datepicker	0	0
✅	buildo/react-cookie-banner	0	0
✅	buildo/react-autosize-textarea	0	0
✅	buildo/react-input-link	0	0
✅	buildo/react-flexview	0	0
✅	buildo/react-placeholder	0	0
✅	buildo/local-date	0	0
✅	buildo/formo	0	0
✅	buildo/hophop	0	0
✅	buildo/nemobot	0	0
✅	buildo/prisma	0	0
✅	buildo/pledge	0	0

[gabro]

(did I forget any project?)

[giogonzo]

lexdoit?

[gabro]

lol, woops.

[gabro]

mm, lexdoit is a tricky one, I think I'll work on linto a little bit to make it work

[FrancescoCioria]

also:

• rc-datepicker
• react-cookie-banner
• react-autosize-textarea
• react-input-link
• react-flexview
• react-placeholder (or not :P)
• local-date
• nemobot
• prisma

PR: from the list above I would only test nemobot and prisma as they're the only ones continuosly deployed (for the other ones it's no big issue if eslint breaks)

[gabro]

Well, including all the projects above, linto produces a report in less than 40s on my machine :)

	repo	errors	warnings
✅	buildo/aliniq	0	0
✅	buildo/web-shared	0	0
✅	buildo/lexdoit	0	0
✅	buildo/ipercron	0	0
✅	buildo/bobafett	0	0
✅	buildo/avenger	0	0
✅	buildo/react-components	0	0
✅	buildo/rc-datepicker	0	0
✅	buildo/react-cookie-banner	0	0
✅	buildo/react-autosize-textarea	0	0
✅	buildo/react-input-link	0	0
✅	buildo/react-flexview	0	0
✅	buildo/react-placeholder	0	0
✅	buildo/local-date	0	0
✅	buildo/formo	0	0
✅	buildo/hophop	0	0
✅	buildo/nemobot	0	0
✅	buildo/prisma	0	0
✅	buildo/pledge	0	0

[dhinus]

💯 I also tested it on the contactlab repos (added to master in #100 but not tested in this PR), no errors.

[nemobot]