TinyMCE table cellpadding/spacing

Initial issue request

When a user creates a table with the TinyMCE editor it has no cell padding and it's kind of hard to edit (see attached screenshot).

Additionally almost always it makes sense to have a padding for a table so it is possible to distinguish the individual cells.

Although it's possible to set a table class that adds formatting (and padding), it is not straightforward for the user how to find the related option to do this.

Also setting the cellpadding/spacing in the table properties does not seem to have any effect. (See second screenshot) - Tested with Firefox 60

Suggestion:

• add a default td/th padding to the content.css stylesheet
• add a table class that sets the padding to zero
• remove the cellpadding/spacing configuration option from TinyMCE or alternatively use inline style attributes to implement it

Implemented Solution

• Adding b_default to new tables that are edited with the integrated HTML editor that adds a standard padding. 
• External edited content must configure option in single page to not embed OO CSS file
• External created QTI questions with tables must add an appropriate CSS class or style to add the padding

For reasoning see discussion on this issue