ascanrules: Tiddy up ExternalRedirectScanRule

- CHANGELOG > Add re-ordering note.
- ExternalRedirectScanRule > Use an enum for payloads & types. Move some
logic to be within the payloads enum for simplicity. Move payload counts
per Strength logic to init method and use a simplified case structure.
Remove unnecessary comments.
- ExternalRedirectScanRuleUnitTest > Remove unnecessary assignments. Use
isEmpty vs length greater than zero.

Signed-off-by: kingthorin <[email protected]>

Author: kingthorin

addOns/ascanrules/CHANGELOG.md

@@ -16,7 +16,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
     - SQL Injection - PostgreSQL
 - The Remote OS Command Injection scan rule has been broken into two rules; one feedback based, and one time based (Issue 7341). This includes assigning the time based rule ID 90037.
 - For Alerts raised by the SQL Injection scan rules the Attack field values are now simply the payload, not an assembled description.
-- Maintenance changes.
+- The External Redirect scan rule payload were slightly re-ordered to prioritize HTTPS variants.
 
 ### Added
 - Rules (as applicable) have been tagged in relation to HIPAA and PCI DSS.