[llvm] [docs] Add beginner-focused office hours (PR #80308)

[Nick Desaulniers via llvm-commits]

================
@@ -331,6 +331,11 @@ don't find anyone present, chances are they happen to be off that day.
     - Monthly, 4th Wednesday of the month at 9:30am PT, for 30 minutes.
     - `Google meet <https://meet.google.com/pdd-dibg-cwv>`__
     - English
+  * - Rotating hosts
+    - Getting Started, beginner questions, new contributors.
+    - Every Tuesday at 2 PM ET (11 AM PT), for 30 minutes.
----------------
nickdesaulniers wrote:

oh! great idea!

https://github.com/llvm/llvm-project/pull/80308