Deprecate implied_halo

The bulk update request #25275 (forum #276938) has been rejected by @War6t2.

zetsubousensei said:

No nontraditional is completely separate from implied. I agree its a mess and agree with others that @war6t2 should reject these BURs and make them in a new thread called "grouping nontraditional halos" or "making a traditional halo" tag.

We can have a more clear discussion there.

Done forum #277093.