I/6106: Introduced color pickers in the table and table cell property forms

[oleq]

Suggested merge commit message (convention)

Feature: Introduced color pickers in the table and table cell property forms. Introduced config.table.tableProperties and config.table.tableCellProperties configurations. Closes ckeditor/ckeditor5/issues/6106.

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Additional information

Requires:

• I/6106: Added styles for the color input ckeditor5-theme-lark#266 (styles for the picker, some styles refactoring)
• I/6106: Moved normalizeColorOptions() and getLocalizedColorOptions() ckeditor5-ui#541 (added color grid utils that are now common for ckeditor5-table and ckeditor5-font)
• I/6106: Moved normalizeColorOptions() and getLocalizedColorOptions() ckeditor5-font#59 (moved color grid utils to ckeditor5-ui)

Some follow-ups

• Unify color palette configuration data format across all packages and features ckeditor5#6237 (we need a single color palette configuration for all editor features, now what we have is a mess).
• All LabelView instances should have text overflow ellipsis ckeditor5#6238 (let's have text ellipsis on all labels across the UI).
• Disable dangling commas across the project ckeditor5#6246 (get rid of dangling commas in the project)

[jodator]

Follow-ups:

• Make color picker keyboard accessible ckeditor5#6239 (keyboard access to the color picker)

[jodator]

Small changes are required:

1. If you think that we should go with table.borderColors instead of table.border.colors (without waiting for @Reinmar) then we're on the same page here as I'm for borderColors :)
2. The tests file for new class requires some cleanup.

For me this can be closed after the changes are applied.

[coveralls]

Coverage remained the same at 100.0% when pulling 3bb62eb on i/6106 into b0c0591 on master.

[Reinmar]

One more followup ckeditor/ckeditor5#6241.

[Reinmar]

cc @ckeditor/qa-team

[Mgsy]

Looks good 👍