Add support for puppetServer.extraConfigMaps

[tom-ph]

Use Case

Currently config maps can only be specified for entrypoint scripts and for puppetserver custom config files.
It would be very useful to also support extra configmaps.
For me the use case would be to add a custom autosign script, since autosign=true strategy is not suitable for a production environment.

Describe the Solution You Would Like

It should be possible to specify extraConfigMaps to embed as volume mounts in the puppetserver pods. An optional defaultMode key it is also important to allow making the configMap executable.

Describe Alternatives You've Considered

Currently I mount the configMap as an entrypoint script. This is not ideal because of the script location and of the fact that I had to edit the script to handle the first execution as entrypoint.

Additional Context

I will be happy to help with a pull request if needed.

[toggetit]

Hello! This will be a very useful feature. Vote for it!
In my case I need to mount some additional files in various locations of puppetmaster pods (As I can see now it's possible to mount files only in /etc/puppetlab/puppetserver/conf.d/ via custom.configmaps). For example some Foreman-related stuff - example one, example two like a:
/etc/puppetlabs/puppet/node.rb
or
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/reports/foreman.rb