test: Add test to verify npm-registry-mock version

I keep getting myself into weird cases where I have an outdated copy of
npm-registry-mock, and so tests fail, and I spend several minutes digging
only to find that it's because I didn't update after the package.json dep
changed.

Add a test to alert to this situation, which will run BEFORE all the other
tests start failing horribly.
view: handle unpublished packages properly
make ignore-scripts test quieter
default to only running 'tap' tests

move other non-standalone tests to test-legacy, and run them all
on 'test-all'
doc: Add canonical url
fix failing test on linux

The GNU shell returns a code and no signal if it gets a SIGSEGV
signal, so we have to skip this. Hat tip to @tjfontaine
v1.4.7
Fix tests

the tests were depending on a warm cache, as npm was calling to
a server on 1331 but the mock-registry was serving packages from
another port. now a temporary cache location is used to avoid
that the tests don't fail as they are getting everything from
the cache.

the server which served the metadata was removed, the metadata is
now served by the mock-registry itself, so npm can also install
from there.

furthermore the package metadata was separated in files.