Fix section header color on Find Issues page
Set max-width instead of percentage to avoid too small table width on small screens
Increase portlet margins
Increase margins on Favorite Filters portlet rows

Use the same margins (8px) for rows like on Show Saved Filter portlets.
Fix style of Issue Navigator table

Use similar style like on Show Saved Filter portlet table

* Remove left and right cell borders
* Add more space between cells
* Increase font size