Added 'AdaptiveCardDesignerHost' Control

[fabiofranzini]

Q	A
Bug fix?	[ ]
New feature?	[X]
New sample?	[ ]
Related issues?	mentioned in #1237

What's in this Pull Request?

Implementation of the Adaptive Card Designer control as reusable react control.
To better implement this control and avoid code duplication, I had to refactor the "Adaptive Card Host" control due to share more code between the 'AdaptiveCardHost' and 'AdaptiveCardHostDesigner' controls.

I deleted the Fluent UI themes that were previously local to the 'AdaptiveCardHost' control and reused those placed in the 'common' folder, to use the latest version of the Teams theme implementations, used by the 'EnhancedThemeProvider' control.

Given the nature of the refactoring, I'm available for any clarifications.

Thanks!

[joelfmrodrigues]

@fabiofranzini another awesome PR 😁
Please give us some time to review as there are a lot of files

[fabiofranzini]

@joelfmrodrigues tell me if you need a call to understand all refactored code of "AdaptiveCardHost" control.
I'm aware of the change, but it was necessary to share the code between the two controls better. 🙂

[AJIXuMuK]

I really-really-really sorry @fabiofranzini for the long delay.
Finally able to review the PR.

[fabiofranzini]

Don't worries and thanks for your review! I'm on vacation now, I'll try to do that fixes in the next few days. Thanks again

[fabiofranzini]

@AJIXuMuK I've closed all change requests 🙂

[AJIXuMuK]

@AJIXuMuK I've closed all change requests 🙂

Thanks @fabiofranzini!
Could you also resolve conflicts so I could easily merge the PR?
Thanks!

[fabiofranzini]

@AJIXuMuK done! Thanks for another code review! 🙂