I/6112: Implemented the table properties form

[oleq]

Suggested merge commit message (convention)

Feature: Implemented the table properties form. Closes ckeditor/ckeditor5#6112.

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Additional information

CI and the constellation

Requires

• ckeditor5-ui — the new property allowing to make the toolbar compact (for all alignment toolbars in both table and table cell properties forms)
• ckeditor5-theme-lark:
  • styles for the compact toolbar,
  • styles fro the table properties form,
  • I found out that we didn't separate wireframe and theme styles in the previous PR so this PR does that
  • styles for private components like FormRowView and FormHeaderView.

Remarks

TablePropertiesUI and TableCellPropertiesUI are very similar (same with the views). At first, I wanted to create a base class (classes) for all of them (and/or a tool to help compose them) but then I figured this may not be the best idea because even though at this moment they are very similar, they may diverge in the future and this will be a situation with an unmaintainable base class (or set of tools).

So, long story short, I don't like this huge code duplication (in UI and View classes) but at the same time, I'm worried that extracting the common pieces will not be good in the long run.

[coveralls]

Coverage remained the same at 100.0% when pulling f8d8d07 on i/6112 into 1eb4b4c on master.

[jodator]

At first, I wanted to create a base class (classes) for all of them (and/or a tool to help compose them) but then I figured this may not be the best idea because even though at this moment they are very similar, they may diverge in the future and this will be a situation with an unmaintainable base class (or set of tools).

I had a similar feeling about all the command classes. There are two base classes but it is not a big deal to refactor them later if needed. The code duplication at this stage is OK IMO.

[jodator]

I could nitpick to that one thing which I actually change before merging. So there's a green light from me.