Primarily this protects against accidentally polling with the default interval
of 10ms. Setting these defaults may also make some tests simpler because they
don't need to override the defaults.
Various different tests all have their own poll intervals. As a start towards
consolidating that, the interval from test/e2e/framework/pod (as one of the
most common cases for polling) is moved into the framework.
Changing other helper packages and tests needs to follow.
This consolidates timeout handling. In the future, configuration of all
timeouts via a configuration file might get added. For now, the same three
legacy command line flags for the timeouts that get moved continue to be
supported.
