Add specific permission to administer data-dictionary settings

[tiffneybare]

Some sites may not want users who manage data publishing to have the very broad 'Administer site configuration' permission in order to access the data dictionary settings screen.

QA Steps

• Add the new administer data dictionary settings permission to an existing role
• Create a user with that role
• Log in as the new user
• Confirm you have access to the following page: /admin/dkan/data-dictionary/settings

[janette]

@tiffneybare I think it would be better to modify the role permissions on the project as we don't want this exposed to roles that just need access to edit content.

[janette]

Adding "Metastore" to the permission titles to follow the pattern set by the Datastore and Harvest modules.