Update Install For Windows

[jobannon]

Summary

• This PR updates installation instructions for Windows users
• Indication to use PowerShell over Command Prompt.
• Closes Minor documentation issue #494

Screenshots

[robotdan]

Nice work @jobannon!

Just to close the loop, I think we are good - but we may want to just do a sanity check on the following items to see if any updates are necessary in these other places where we describe the Windows install.

1. FastPath install doc.
   https://fusionauth.io/docs/v1/tech/installation-guide/fast-path/ - found here: https://github.com/FusionAuth/fusionauth-site/blob/master/site/docs/v1/tech/installation-guide/fast-path.adoc
2. README.md in the Install repo : https://github.com/FusionAuth/fusionauth-install

[jobannon]

Thanks, @robotdan!

1 . I have verified that the includes file updated in this PR should account for the additional location of https://fusionauth.io/docs/v1/tech/installation-guide/fast-path

2. A separate PR was opened to address readme - Update Readme to Reflect Windows Users Needing PowerShell to Install. fusionauth-install#7