In Hugo 0.57 we needed to delay the page metadata initialization until we had built the page graph.
This introduced a regression in that we now created taxonomy entries for expired pages.
This fixes that by moving the "should not build" filter before we assemble the taxonomies.
Fixes#6213
This is preparation for #6041.
For historic reasons, the code for bulding the section tree and the taxonomies were very much separate.
This works, but makes it hard to extend, maintain, and possibly not so fast as it could be.
This simplification also introduces 3 slightly breaking changes, which I suspect most people will be pleased about. See referenced issues:
This commit also switches the radix tree dependency to a mutable implementation: github.com/armon/go-radix.
Fixes#6154Fixes#6153Fixes#6152
