(MAINT) Add PuppetDB info to the running from source docs
(MAINT) Add PuppetDB info to the running from source docs

This commit adds some docs on running a source based PuppetDB instance
with a source based Puppet Server instances. I also added some
clarification around invoking the Puppet Agent that I found helpful
when setting up a dev environment.

er0ck/puppetserver,puppetlabs/puppetserver,rlinehan/puppet-server,camlow325/puppet-server,camlow325/puppet-server,rlinehan/puppetserver,camlow325/puppet-server,shrug/puppet-server,puppetlabs/puppetserver,er0ck/puppetserver,shrug/puppet-server,rlinehan/puppet-server,camlow325/puppetserver,camlow325/puppetserver,puppetlabs/puppet-server,puppetlabs/puppet-server,camlow325/puppetserver,puppetlabs/puppet-server,rlinehan/puppetserver,shrug/puppet-server,camlow325/puppetserver,puppetlabs/puppetserver,puppetlabs/puppetserver,rlinehan/puppetserver,er0ck/puppetserver,rlinehan/puppetserver,er0ck/puppetserver,shrug/puppet-server,rlinehan/puppet-server