Added small and large icons to pages editor

[valadas]

Closes #109

Summary

Adds back a UI to set icons on pages (small and large icon).
This feature was part of Dnn already and all the backend still works, it was just missing a UI to manage those images. I have tried to implement it as much as possible as the Portal Logo and favIcon for a consistent user experience

[dnfclas]

All CLA requirements met.

[mitchelsellers]

LGTM - Consistency here matches the other implementations

[ashishpd]

Can we include an 'after' screenshot where possible? Also, where are these icons used?

[sleupold]

@ashishpd The Icons may be used in Menu or Skin

[valadas]

The icons can be used anywhere, commonly in menus, skins, but anything else can access them through the TabInfo data.

Here is the screenshot of the feature @ashishpd :

[sleupold]

@valadas
The "Enable Scheduling" toggle doesn't seem to be connected to the icons, am I correct?
maybe both sliders need a bit more space above.

[valadas]

@sleupold Or all the rest needs a little bit less spacing :) Either Or.... But yeah, that could be improved, it is merged now, so maybe some other time, the feature is back at least.