Rename subdir kcontrol to kcontrol5

in distributions the doc packages for kdelibs4support and kde-runtime are usually designed to be co-installable,
but this fails in some distributions due to conflicting file paths, therefore:

* subdir kcontrol is renamed to kcontrol5
* install target for kcm_ssl docbook changed to kcontrol5
* X-DocPath changed to kcontrol5/kcm_ssl/index.html
REVIEW:129209