chore(tazjin/predlozhnik): move to //corp

This is currently hosted by the company, and I'm assigning my
copyright to the company, which also runs an ad placement on the page.

Note that the NixOS module for hosting it has not been moved yet.

Change-Id: Iba9e1cab9370faa79e43c3344fbfbbbabead50b3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7857
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI

corp/russian/README.md

@@ -0,0 +1,9 @@
+//corp/russian
+==============
+
+This folder contains TVL corp projects related to the Russian
+language, such as the code powering
+[Предложник](https://predlozhnik.ru).
+
+Unless otherwise specified, all rights to these projects are reserved
+by ООО "ТВЛ".

users/tazjin/nixos/modules/predlozhnik.nix

@@ -3,7 +3,7 @@
 
 {
   services.nginx.virtualHosts."predlozhnik.ru" = {
-    root = depot.users.tazjin.predlozhnik;
+    root = depot.corp.russian.predlozhnik;
     enableACME = true;
     forceSSL = true;
   };