merge download pages (#14686)

- update .htaccess
- warnings.wmi: recommend to use Pluggable Transports (#25098)

- add slackbuilds (fixes #26307)
- link to Tor Browser Hacking Guide (#24255)
- link to OnionBrowser with warning (fixes #26133)
- tor: add oldstable, testing and beta (#17805, #26298)
- update links to download page (#27131)

- replace javascript with css accordion (#27540)
- css: move OS box up, clean indention

.htaccess

@@ -61,7 +61,10 @@ RewriteRule ^contact(.*) /about/contact$1 [R=301,L]
 # Download websites
 RewriteRule ^download/$ /download/download [R=301,L]
 RewriteRule ^download.html(.*) /download/download.html$1 [R=301,L]
-RewriteRule ^easy-download(.*) /download/download-easy$1 [R=301,L]
+RewriteRule ^easy-download(.*) /download/download$1 [R=301,L]
+RewriteRule ^download-easy(.*) /download/download$1 [R=301,L]
+RewriteRule ^download-unix(.*) /download/download$1 [R=301,L]
+RewriteRule ^tor(.*) /download/download [R=301,L]
 
 # Relays
 RewriteRule ^relays(.*) /getinvolved/relays [R=301,L]