[WIP] Folder support

[geofjamg]

• Do you want to request a feature or report a bug?
  Feature

• What is the current behavior?
  With the current version we can only access to cases of one folder but there is no way to access case of child folders.

• What is the expected behavior?
  We could allow access to child folders cases like this

/cases/{folder}/{caseName}

and for instance

/cases/CGMES/FO/2020/01/01/202001010030FO1.zip

We probably need to use URLEncore and URLDecode to support any folder character.

To browse folders we could also provide:

/folders/{folder}

=>

[
    folder1,
    folder2,
    folder3,
]

• What is the motivation / use case for changing the behavior?

• Please tell us about your environment:

  • PowSyBl Version: ...
  • OS Version: ...

• Other information (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. stackoverflow, spectrum, etc)

(if a question doesn't apply, you can delete it)