Missing screenshots in Flex administration docs

[Karmalakas]

Here are couple of pages with missing screenshots (404 errors)

• grav-learn/pages/08.advanced/01.flex/01.administration/docs.17.md
• grav-learn/pages/08.advanced/01.flex/01.administration/03.configuration/docs.17.md

[Andy Miller]

Yes we never got around to them. Its on our list. These broken images serve as placeholders for us at the mo so we know what needs to be done.