Buttons Block: Add font-size controls

[alaczek]

Is your feature request related to a problem? Please describe.
It would be great to be able to control button size (both font-size and padding).

Describe the solution you'd like
This could be done by:

• having separate padding and font-size settings
• combining both in one setting. I quite like how this is done in Atomic Blocks plugin:

Separate settings would give us more control while the combined approach makes for a simpler UI.

[paaljoachim]

I believe that the Buttons block could also have Typography controls.
I added the issue for it here: #29112

Margin/padding would be inside a Dimensions panel mentioned in your issue here: #29098

I believe we can close this issue. What do you think @alaczek ?

[alaczek]

Yep, I think so!