Update own-webserver guide and add sample Apache configuration

This supersedes #59 (Github Pull Request),
which was greatly beneficial in creating our sample Apache configuration.

examples/apache/matrix-riot-web.conf

@@ -0,0 +1,41 @@
+# This is a sample file demonstrating how to set up reverse-proxy for the riot.DOMAIN.
+# If you're not using Riot (`matrix_riot_web_enabled: false`), you won't need this.
+
+<VirtualHost *:80>
+	ServerName riot.DOMAIN
+
+	# Map /.well-known/acme-challenge to the certbot server
+	# If you manage SSL certificates by yourself, this will differ.
+	<Location /.well-known/acme-challenge>
+		ProxyPreserveHost On
+		ProxyRequests Off
+		ProxyVia On
+		ProxyPass http://localhost:2402/.well-known/acme-challenge
+	</Location>
+
+	Redirect permanent / https://riot.DOMAIN/
+</VirtualHost>
+
+<VirtualHost *:443>
+	ServerName riot.DOMAIN
+
+	SSLEngine On
+
+	# If you manage SSL certificates by yourself, these paths will differ.
+	SSLCertificateFile /matrix/ssl/config/live/riot.DOMAIN/fullchain.pem
+	SSLCertificateKeyFile /matrix/ssl/config/live/riot.DOMAIN/privkey.pem
+
+	SSLProxyEngine on
+	SSLProxyProtocol +TLSv1.1 +TLSv1.2 +TLSv1.3
+	SSLCipherSuite EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH
+
+	ProxyPreserveHost On
+	ProxyRequests Off
+	ProxyVia On
+
+	ProxyPass / http://localhost:8765/
+	ProxyPassReverse / http://localhost:8765/
+
+	ErrorLog ${APACHE_LOG_DIR}/riot.DOMAIN-error.log
+	CustomLog ${APACHE_LOG_DIR}/riot.DOMAIN-access.log combined
+</VirtualHost>