(PDB-2518) Remove links from the README.md
(PDB-2518) Remove links from the README.md

The README.md has links to our markdown files for many years, however linking
via our github documentation has never worked well. Instead, I have removed this
sectioning, and pointed the user directly at our published documentation.

Signed-off-by: Ken Barber <470bc578162732ac7f9d387d34c4af4ca6e1b6f7@bob.sh>

mullr/puppetdb,waynr/puppetdb,kbarber/puppetdb,puppetlabs/puppetdb,mullr/puppetdb,waynr/puppetdb,waynr/puppetdb,senior/puppetdb,rbrw/puppetdb,senior/puppetdb,puppetlabs/puppetdb,rbrw/puppetdb,kbarber/puppetdb,mullr/puppetdb,puppetlabs/puppetdb,senior/puppetdb,rbrw/puppetdb,puppetlabs/puppetdb,senior/puppetdb,kbarber/puppetdb,waynr/puppetdb,rbrw/puppetdb,mullr/puppetdb,rbrw/puppetdb,kbarber/puppetdb,mullr/puppetdb,puppetlabs/puppetdb