Add Pre-Flight Checks to initial scripting

[adilio]

As a way to help users fall only into the "Pit of Success" (😂), it would be helpful to have some pre-flight checks run by the user, to ensure they have all the pieces in place before beginning to deploy. This could be Pester tests, or simple functions that check for certain prerequisites. This process could also be interactive, to get input from the end-user as well.

Some ideas for prerequisites to check for:

• Does the C4B Server have Internet access?
• Is it going to be Internet-enabled? If so:
  • Do you have a public IP?
  • Do you have a Fully-Qualified Domain Name (FQDN) resolving to that public IP?
  • Do you have an SSL certificate with an exportable private key for this FQDN?

[JPRuskin]

Other things that might be handy (possibly even just with a soft-fail / warning):

• Does the CPU have enough cores?
• ...enough memory?
• ...enough disk space?

[ryanrichter94]

@adilio and myself wrote a PDF checklist of pre-flight requirements for QSG and Azure QDE tonight.

[adilio]

Here is a link to the checklist in its current version:
C4B Preflight Checklist

We should incorporate some of these checks into the begin block of the initial scripting.