Enable HTML Export for whole wiki

Goal: Export all Spaces in a wiki in one HTML export

• (Optional) Create new (Sub-) Wiki
• You're on /Main/ ("Home")
• Create a new Space "Foo" , Create a Space "Bar" under "Foo"
  Foo is a Top-Level Space parallel to Main
• Create another Top-Level Space "Foobar" next to "Foo"

Now export all spaces as one HTML Export -> This is not possible.

• If you are on /Main/ , you can only export this page (see export-main.png)
• If you are on /Foo/ you can only export this space (Foo.WebHome and Bar.WebHome) (see export-foo.png)

If you have several top-level-spaces, you have to export them all separately