Update modules base class (WebModule) and <meta.xml> structure

Updated \Site\components\WebModule:
- Added methods: getAlias()
- Added using cache to store parsed <meta.xml> as an array.
- Updated methods: getMeta($property)
- Deleted methods: getModuleAuthor(), getModuleDescription(), getAdminRoute(), getAdminLabel()

Updated <meta.xml> structure:
- Added:	<name>
- Added:	<admin.controller>
- Deleted:	<managment>

Exclude modules that are not WebModule descendants from the main admin page.