Use Assignee instead of translator in tmgmt_local

Sometimes when this information is shown to the user, we don't want to see it as assignee, there's some cases we will want to see it just as user, for example in the Job Translation Info now we have "Translation job is not assigned to any translator." change to "Translation job is not assigned to any assignee." is not really nice, would be better to have "Translation job is not assigned to any user."

In the code we want to use always assignee, but when we show info to the user we prefer to use "user".

+++ b/translators/tmgmt_local/src/Tests/LocalTranslatorTest.php
@@ -193,7 +193,7 @@ class LocalTranslatorTest extends TMGMTTestBase {
     $this->assertEqual($xpath->option[0], 'Local translator (auto created) (unsupported)');
-    $this->localTranslator = $this->drupalCreateUser($this->localTranslatorPermissions);
+    $this->Assignee = $this->drupalCreateUser($this->localTranslatorPermissions);
 
     // The same when there is a single role.

The first letter of a property must not be uppercase.

@@ -766,10 +766,10 @@ class LocalTranslatorTest extends TMGMTTestBase {
     $this->drupalPostForm(NULL, $edit, t('Assign tasks'));
-    $this->assertText(t('Assigned 1 to translator @translator.', ['@translator' => $local_translator->getAccountName()]));
+    $this->assertText(t('Assigned 1 to translator @translator.', ['@translator' => $assignee->getAccountName()]));
   }
 

This is not a @translator, maybe @user