The hst:page below an XPage document should be skipped between draft and unpublished variant

In CMS-13382 the hst cnd was changed to:

[hst:page] > hippostdpubwf:auditTrace, hippostd:skipdraft mixin
+ hst:page (hst:component) = hst:component

However, the above is wrong: the 'hst:page' mixin namely is added to the document variant, but the child node 'hst:page' should have the hippostd:skipdraft marker! The cnd is also confusing since 'hst:page' is the mixin as well as the child node name. Let's change it into

[hst:page] > hst:component, hippostd:skipdraft

[hst:xpage] > hippostdpubwf:audittrace mixin
+ hst:page (hst:page) = hst:page

to make it more clear

Also add an integration test for it

As part of this issue, though different but in the same area and very simple, I rename

[hippostdpubwf:auditTrace] > nt:base mixin

to

[hippostdpubwf:audittrace] > nt:base mixin

since we do not use camel casing any where in repository cnd's so we better keep it consistent