Add additional formatting options to the Table block inspector sidebar

[SymbolicallyMe]

The Issue:

Text within a table cell of the Table block is missing a few formatting options. Just like the Paragraph block, the Table block should be able to apply a font size, background and/or text color to each table cell.

The Solution:

Add font size, background and text color options to the inspector sidebar.

[mtias]

Closing in favor of #6923.