feat(home): clarify 5chan is serverless app, use current hostname for share links

- Homepage infobox: merged copy into single line explaining app nature and download link
- Share links (Copy direct link): use window.location.origin instead of hardcoded 5chan.app
- Settings version link: use current origin
- FAQ: add 'Is 5chan just this website?' entry under Basics
- Remove pleb.bz from CHAN_5_HOSTNAMES

public/translations/en/default.json

@@ -2,7 +2,7 @@
   "what_is_5chan": "What is 5chan?",
   "go": "go",
   "5chan_description": "5chan is a fully decentralized and open-source imageboard, where anyone can create and cryptographically own unlimited boards. Board owners host and moderate their board, and set its <1>Rules</1>. All data is text-only and it's shared peer-to-peer, including links to embed images. Check out the <2>FAQs</2> to learn more. Feel free to click on a board below that interests you and jump right in!",
-  "no_global_rules_info": "You can always connect to any board, fully P2P, nobody can stop you. Simply paste its address in the search field above.",
+  "no_global_rules_info": "5chan is a serverless app, this website is just one way to open it. To avoid relying on the website's uptime, <1>download a release</1>.",
   "boards": "boards",
   "popular_threads": "Popular threads",
   "options": "Options",