feat: New NetScaler quickstart

[jcountsNR]

Summary

NetScaler quickstart. They have an integration already live, so this just calls that out and shows how to set it up.

Pre merge checklist

• Did you check you NRQL syntax? - Does it work?
• Did you include a Data source and Documentation reference?
• Are all documentation links publicly accessible?
• Did you check your descriptive content for voice and tone?
• Did you check your descriptive content for spelling and grammar errors?
• Did you review your content with a subject matter expert? (e.g. a Browser agent quickstart is reviewed with a member of the Browser Agent team)

Dashboards

• Does the PR contain a screenshot for each of your dashboards?
• Do your screenshots show data?
• Has the sanitization script been run on each dashboard?

Alerts

• Did you check that your alerts actually work?
• Are you trying to create standalone alerts? Standalone alerts are deprecated. They should only be included in quickstarts.