Upgraded to Fork CMS 3.7 & 3.8

* Modified filenames to be compatible with Fork 3.7 & 3.8
* Changed paths inside files to the new capitalized files&folders

Can someone do a quick check of this commit? Not sure about the `info.xml` (those hard-coded widgets/modules should they be capitalized or not? Triton still uses lowercase and underscored module names & actions like in <3.7 versions).

I also noticed that Fork CMS 3.8 still contains templates with lowercase and underscore: `/src/Frontend/Modules/Faq/Layout/Templates/Mails/own_question.tpl` for example. But that's more of a Fork bug, so I haven't changed these files inside the template to a capitalized version.