HPCC-11731 Changing banner style does not refresh local banner

Banner is refreshed on any style or text change.
Calculate banner height based on content.
Added support for ShowBanner.
Remove <font> and replaced with style.

Fixes HPCC-11731
Fixes HPCC-11726

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #6096 from GordonSmith/HPCC-11731

HPCC-11731 Changing banner style does not refresh local banner

Reviewed-By: Miguel Vazquez <miguel.vazquez@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>