Fixes #16982 - Scope properly when no taxonomies are set

The default scope for hosts and other objects did not restrict
properly by taxonomies. An user without organizations or
locations, could do anything it's permissions allow to.
The list of hosts was unrestricted and showed hosts in...

refs #17526 - reset taxonomy.current after each test

The shared "ignores the taxable_type if current taxonomy ignores it"
test failed to reset the taxonomy in teardown, instead using the setup
routine. This causes failures in different test cases when the test was...

Fixes #17526 - Taxonomy.ignore? does not work with "any context"

In this scenario:

1. User has one organization - "E-Corp" - this organization allows the
user to see every hostgroup (via selecting "all host groups" when
editing the organization).

2. User has a location "Czech republic" that also includes all host...