Type the autentication provider passwords as nullable strings

For historic reasons we couldn't add a nullable type hint before
nullable type hints were supported by our target php versions. This is
now possible.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

lib/private/Authentication/Token/DefaultTokenProvider.php

@@ -71,21 +71,12 @@ class DefaultTokenProvider implements IProvider {
 	}
 
 	/**
-	 * Create and persist a new token
-	 *
-	 * @param string $token
-	 * @param string $uid
-	 * @param string $loginName
-	 * @param string|null $password
-	 * @param string $name
-	 * @param int $type token type
-	 * @param int $remember whether the session token should be used for remember-me
-	 * @return IToken
+	 * {@inheritDoc}
 	 */
 	public function generateToken(string $token,
 								  string $uid,
 								  string $loginName,
-								  $password,
+								  ?string $password,
 								  string $name,
 								  int $type = IToken::TEMPORARY_TOKEN,
 								  int $remember = IToken::DO_NOT_REMEMBER): IToken {

lib/private/Authentication/Token/IProvider.php

@@ -53,7 +53,7 @@ interface IProvider {
 	public function generateToken(string $token,
 								  string $uid,
 								  string $loginName,
-								  $password,
+								  ?string $password,
 								  string $name,
 								  int $type = IToken::TEMPORARY_TOKEN,
 								  int $remember = IToken::DO_NOT_REMEMBER): IToken;

lib/private/Authentication/Token/PublicKeyTokenProvider.php

@@ -80,7 +80,7 @@ class PublicKeyTokenProvider implements IProvider {
 	public function generateToken(string $token,
 								  string $uid,
 								  string $loginName,
-								  $password,
+								  ?string $password,
 								  string $name,
 								  int $type = IToken::TEMPORARY_TOKEN,
 								  int $remember = IToken::DO_NOT_REMEMBER): IToken {