This commit fixes how the border is applied in an image block.
- the border is applied to the wrapping table cell instead of the image
- we need to move classes related to border styles to the cell so that related styles are inlined in the proper place
- the caption is put in an additional table so that it doesn't extend the border when it is longer than the image
- rounded image styles are now applied to the wrapper and the image
[MAILPOET-6280]
9829c96caa