LaTeX updates and consistent newline support in documentation

[lorenzschmid]

This PR improves the LaTeX documentation layout and was done in consultation with @stefanlippuner.

• Add register description after register summary if register contains fields/children.
  • Single newline are respected (by adding \\).
  • Multiple newline are left and treated by LaTeX as a new paragraph.
• Allow line breaks inside bit field description.
  • Each newline is simply replaced with a \newline command (similar behavior than \\).
• Remove the access column from the bit field table to gain more width for the description column.
  • Not necessary to state per bit field as access type is set per register.
  • Add access type to the register summary instead.
• Allow bit field table to break at page end and spread over multiple pages.
• Adapt long table layout.
  • Remove caption.
  • Add row header to be shown on each page of a continuous table.
• Improve escaping of special characters.

There is one change concerning the HTML documentation: Similar to LaTeX, newlines are now supported in the bit field. In order to do so, the <ul> lists have been changed to descriptive lists, i.e., <dl>, which slightly alters how they look like.

[tgingold-cern]

Thanks!