Anchor VRF RT search by default

This gives a more intuitive search when listing VRFs and specifying the
rt argument. rt = 123:1 will return the VRF with RT 123:1 and not 123:10
or anything else regex matching 123:1. It's still possible to get all
VRF with RTs starting with 123:1 by searching for '123:1.*'.

Fixes #258
Fix default CLI args to not regex anchor

Kind of part of #258
Merge branch 'cli-vrf-rt-list'