chore(asf): Update GitHub repo metadata

[dpogue]

• Corrects the repo topics to more accurately reflect the languages actually in use (no more "cplusplus" or "csharp" topics)
• Adds the Hacktoberfest opt-in topic
• Turns off GitHub Projects for the repo (we use them at the org instead)
• Aligns with our goal of using squash commits when merging pull requests by disabling the merge and rebase options

[codecov-commenter]

Codecov Report

Merging #1002 into master will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1002   +/-   ##
=======================================
  Coverage   74.91%   74.91%           
=======================================
  Files          13       13           
  Lines        1718     1718           
=======================================
  Hits         1287     1287           
  Misses        431      431           

---

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 0b48eaf...14efe2e. Read the comment docs.