cater for multiple server_urls

[bassonj]

Documentation at puppet.com states that multiple server_urls can be specified

You can use a comma-separated list of URLs if there are multiple PuppetDB instances available. A server_urls config that supports two PuppetDBs would look like:

server_urls = https://puppetdb1.example.com:8081,https://puppetdb2.example.com:8081

This MR changes the puppet_server String into an Array and runs .map on it to allow for multiple puppetdb servers to be specified

[CLAassistant]

All committers have signed the CLA.

[puppet-community-rangefinder]

puppetdb::master::config is a class

Breaking changes to this file WILL impact these 8 modules (exact match):

• cnacorrea-puppet
• aursu-puppet
• ploperations-puppet
• stephenrjohnson-puppet
• abstractit-puppet
• puppetfinland-puppetmaster
• objectiflibre-puppet
• simp-simp

Breaking changes to this file MAY impact these 3 modules (near match):

• example42-psick
• devopera-dopuppetmaster
• theforeman-puppet

puppetdb::master::puppetdb_conf is a class

that may have no external impact to Forge modules.

This module is declared in 33 of 579 indexed public Puppetfiles.

---

These results were generated with Rangefinder, a tool that helps predict the downstream impact of breaking changes to elements used in Puppet modules. You can run this on the command line to get a full report.

Exact matches are those that we can positively identify via namespace and the declaring modules' metadata. Non-namespaced items, such as Puppet 3.x functions, will always be reported as near matches only.

[binford2k]

Also, we probably want a couple spec updates in https://github.com/puppetlabs/puppetlabs-puppetdb/tree/main/spec/unit/classes/master to validate behaviors

[bassonj]

I've updated the approach to deal with either a String or an Array of strings so no regression is introduced.
I've also updated the specs to the best of my abilities.

Please let me know if there's anything else that needs to happen to expedite the acceptance of this change