Relocate reverse-proxy example configurations and update docs/configuring-playbook-own-webserver.md with more details

examples/reverse-proxies/apache/matrix-client-element.conf

@@ -0,0 +1,35 @@
+# This is a sample file demonstrating how to set up reverse-proxy for element.DOMAIN.
+# If you're not using Element (`matrix_client_element_enabled: false`), you won't need this.
+
+<VirtualHost *:80>
+	ServerName element.DOMAIN
+
+	# You may wish to handle the /.well-known/acme-challenge paths here somehow,
+	# if you're using ACME (Let's Encrypt) certificates.
+
+	Redirect permanent / https://element.DOMAIN/
+</VirtualHost>
+
+<VirtualHost *:443>
+	ServerName element.DOMAIN
+
+	SSLEngine On
+
+	# If you manage SSL certificates by yourself, these paths will differ.
+	SSLCertificateFile /matrix/ssl/config/live/element.DOMAIN/fullchain.pem
+	SSLCertificateKeyFile /matrix/ssl/config/live/element.DOMAIN/privkey.pem
+
+	SSLProxyEngine on
+	SSLProxyProtocol +TLSv1.2 +TLSv1.3
+	SSLCipherSuite EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH
+
+	ProxyPreserveHost On
+	ProxyRequests Off
+	ProxyVia On
+
+	ProxyPass / http://127.0.0.1:81/
+	ProxyPassReverse / http://127.0.0.1:81/
+
+	ErrorLog ${APACHE_LOG_DIR}/element.DOMAIN-error.log
+	CustomLog ${APACHE_LOG_DIR}/element.DOMAIN-access.log combined
+</VirtualHost>