nginx 301 'well known' change needed to support http2

[hcoin]

The current nginx config for 'well known' addresses follows the pattern

    location = /.well-known/caldav  { return 301 /remote.php/dav/;  }

which is fine except when nginx is behind a proxy or using http2. In those cases, the redirect adds the non-standard port/protocol (usually 8443 instead of 443) and the direct fails-- as that port is not exposed to the client. I suggest changing all 301's along the lines

    location = /.well-known/caldav  { return 301 https://$server_name/remote.php/dav/; }

which will force the client to use the 443 port, and allow the proxy / load balancing logic to do its work properly.

[joshtrichards]

Duplicate of #899