Add windows-specific dns guidance to beginner tutorials

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#### Feature Description

The Consul beginner tutorials demonstrate queries against Consul's DNS server. The documentation is heavily geared towards unix systems, but could easily be adapted to include windows users.

The two issues I found were:

- 'dig' is not used on Windows. Instead, we use nslookup or (in powershell) Resolve-DnsName.
- I'm not sure of the mechanism behind this, but I couldn't find a way to query Consul DNS on port 8600. I solved this by binding to port 53 in a config file. The problem I see hear is pedagogical - in the tutorial series, config files aren't explained until the tutorial _after_ DNS lookups are introduced. I appreciate very few people will be installing consul without at least knowing what DNS is and how config files work, but it could be a source of frustration.

I think windows users (who often don't choose to be using windows, mind) would benefit from a small box explaining this windows-specific configuration. At least, a pointer to the configuration docs page and the relevent docs for the cmd and PS utilities could speed this process up.

#### Use Case(s)

New windows users learning consul.

Review the Consul beginner tutorials where DNS queries are introduced, then read the configuration documentation and the Windows command and PowerShell references mentioned in the issue. Done means adding a concise Windows-specific note covering nslookup or Resolve-DnsName and the port 8600 configuration path.

Written by the indexing model from the issue text.