tools: lisa-doc-build: Change sphinx command line
tools: lisa-doc-build: Change sphinx command line

* turn warnings into errors to get non-zero return code
* keep going if there are some errors (=warnings)
* build in parallel
* show full traceback if there is an exception

credp/lisa,credp/lisa,ARM-software/lisa,credp/lisa,credp/lisa,ARM-software/lisa,ARM-software/lisa,ARM-software/lisa