Break AphrontDatabaseConnection dependencies on PhabricatorEnv

Summary: We pull "retries" and a doc link from PhabricatorEnv directly. Break these dependencies so the classes can move to libphutil.

Test Plan: Browsed site, triggered a schema exception and verified I still got the useful footer text.

Reviewers: btrahan, vrana

Reviewed By: vrana

CC: aran

Maniphest Tasks: T1283

Differential Revision: https://secure.phabricator.com/D3053

src/infrastructure/storage/connection/mysql/AphrontMySQLDatabaseConnection.php

@@ -52,11 +52,12 @@ final class AphrontMySQLDatabaseConnection
     $user = $this->getConfiguration('user');
     $host = $this->getConfiguration('host');
     $database = $this->getConfiguration('database');
+    $pass = $this->getConfiguration('pass');
 
     $conn = @mysql_connect(
       $host,
       $user,
-      $this->getConfiguration('pass'),
+      $pass,
       $new_link = true,
       $flags = 0);