Remove announcement service

[jgwerner]

• Removes announcement services and tests
• Removes announcement service call from LTI 1.1 authenticator

[codecov]

Codecov Report

Merging #515 (721443f) into main (5552cf0) will decrease coverage by 0.40%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #515      +/-   ##
==========================================
- Coverage   75.94%   75.53%   -0.41%     
==========================================
  Files          17       16       -1     
  Lines        1139     1116      -23     
==========================================
- Hits          865      843      -22     
+ Misses        274      273       -1     

Impacted Files	Coverage Δ
...umidesk/illumidesk/authenticators/authenticator.py	90.90% <ø> (-0.19%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5552cf0...721443f. Read the comment docs.

[Abhi94N]

LGTM