Update analyzer docs with information about analyzers that require authentication

salt/sensoroni/files/analyzers/README.md

@@ -18,6 +18,23 @@ The built-in analyzers support the following observable types:
 | Urlscan                 |✗ |✗|✗|✗|✗|✗|✗|✓|✗|
 | Virustotal              |✓ |✓|✓|✗|✗|✗|✗|✓|✗|
 
+## Authentication
+Many analyzers require authentication, via an API key or similar. The table below illustrates which analyzers require authentication.
+
+| Name                    | Authn Req'd|
+--------------------------|------------|
+[Alienvault OTX](https://otx.alienvault.com/api)            |✓|
+[EmailRep](https://emailrep.io/key)                  |✓|
+[Greynoise](https://www.greynoise.io/plans/community)                 |✓|
+JA3er                     |✗|
+LocalFile                 |✗|
+[Pulsedive](https://pulsedive.com/api/)                 |✓|
+Spamhaus                  |✗|
+Urlhaus                   |✗|
+[Urlscan](https://urlscan.io/docs/api/)                   |✓|
+[Virustotal](https://developers.virustotal.com/reference/overview)                |✓|
+
+
 ## Developer Guide
 
 ### Python