Change paths to Moxiemanager in CMS (#4)

Update LibraryInstaller.php

return a absolute path from getInstallPath()

Add `clxFrontendCms` (#2)

added clxbackendcms

added composer-plugin-api 2.0 compat (#1)

added moxiemanger special case

BC: Added filesystem-folder mappings for mixed-case named packages

we have some packages which casing is important in the filesystem for BC reasons.
since we had to adjust package-names for composer 2.0 to be lower case, we map back to the BC friendly name here

refs CLX84-187

fixed typo

initial checkin