Add deprecation messages to security managers APIs

[just-joshing]

The organization security manager role REST APIs are being sunset (https://gh.io/security-managers-rest-api-sunset) in favor of the organization roles REST APIs.

This change adds deprecation messages to tell consumers which client operations to use instead going forward.

[just-joshing]

I had previously tried updating these operations instead to use the replacement client methods under-the-hood but got feedback to go the deprecation route instead.

[stevehipwell]

LGTM

[gmlewis]

Thank you, @just-joshing and @stevehipwell !
LGTM.
Merging.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.22%. Comparing base (2b8c7fa) to head (9f0b14d).
Report is 217 commits behind head on master.

Additional details and impacted files

@@ Coverage Diff @@## master #3426 +/- ##
==========================================
- Coverage 97.72% 92.22% -5.51% 
==========================================
Files 153 173 +20 Lines 13390 14937 +1547 ==========================================
+ Hits 13085 13775 +690 - Misses 215 1068 +853 - Partials 90 94 +4 

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.