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>

Author: ChristophWurst

lib/private/Authentication/Token/DefaultTokenProvider.php

@@ -85,7 +85,7 @@ public function __construct(DefaultTokenMapper $mapper,
 	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 @@ public function __construct(PublicKeyTokenMapper $mapper,
 	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 {