[core] Support for bridge maintainers' donation URLs (#2102)

lib/BridgeAbstract.php

@@ -40,6 +40,13 @@ abstract class BridgeAbstract implements BridgeInterface {
 	 */
 	const URI = '';
 
+	/**
+	 * Donation URI to the site the bridge is intended to be used for.
+	 *
+	 * Use {@see BridgeAbstract::getDonationURI()} to read this parameter
+	 */
+	const DONATION_URI = '';
+
 	/**
 	 * A brief description of what the bridge can do
 	 *
@@ -341,6 +348,11 @@ abstract class BridgeAbstract implements BridgeInterface {
 		return static::URI;
 	}
 
+	/** {@inheritdoc} */
+	public function getDonationURI(){
+		return static::DONATION_URI;
+	}
+
 	/** {@inheritdoc} */
 	public function getCacheTimeout(){
 		return static::CACHE_TIMEOUT;