[WIP] Reduce boost for postalcode matches in `/v1/search` queries
For many years now, we have often seen queries where incorrect results that happened to match on a postalcode were boosted above the correct match.
Considering that there is no guarantee any particular address or venue record will have a postalcode, this case is in fact fairly common.
I believe our desired outcome is that a postalcode acts only as a 'tiebreaker' between otherwise very similar results.
With that in mind, the current default boost of 20 is far too high.
I just gave this PR a quick test. It does break one of our acceptance tests, but I'm not sure its a good one

There were no other changes to any of our test suites that I could find, but if we ever find something that this PR helps we could merge it.