Add BazelCon preso link to the LS docs

Author: plaird

docs/bjls/README.md

@@ -1,3 +1,8 @@
 ## Bazel Java Language Server
 
 This is the home of the Language Server project docs.
+The product is very basic so far, but more investment will come (said in early 2022).
+
+In the meantime, there is a BazelCon presentation you can watch that covers the ideas.
+Start at the 12 minute mark to see the Language Server portion of the talk:
+- [Eclipse and VS Code IDE Support for Java packages in Bazel](https://www.youtube.com/watch?v=oLnfv2-aGwk)