Facilitate document type icon setup for Designer

Currently, people need to upload their doctype icons manually and create the tree structure if needed. This is cumbersome and should be made simpler.

TODO
In the doctype screen:

• Add a new SVG Icon option below them to upload / select the svg file to use for the icon in web ui
• Help label:

  In Web UI, this icon is displayed in the document creation dialog for your document type.

AC

• SVG Icon option only shows up when web ui is among the dependencies
• When I select a SVG icon, I can only upload a svg file. Other formats are refused.
• When a file is uploaded, I can preview it securely (e.g. the attached test svg file should not be executed by triggering a preview in Studio)
• I can select an already uploaded svg for my document type icon
• When the bundle is generated, the svg is placed in the proper tree structure (created if needed) and named after the web ui convention
  • An existing svg with this name is overwritten
• When I copy a doctype and copy succeeds, the svg is also copied in the designer resources with the new name
  • An existing svg with this name is overwritten
• When I rename a doctype and renaming succeeds, the svg in Designer is renamed accordingly
  • An existing svg with this name is overwritten
• When a doctype is deleted
  • icon copy used for designer is removed as well
  • svg icon is kept in the project resources