added README for data/simulation/small

Author: Saizan

data/simulation/small/README.md

@@ -0,0 +1,11 @@
+# A scenario with 100 nodes
+- Network is randomly generated with Cylindrical topology, and
+  latencies simulating nodes spread across the globe.
+- Uniform stake distribution.
+- Each node has 10 upstream peers with 2000kBs links.
+- Three topology files differing only in number of CPU cores.
+- One config file for single-stage and one for send-recv voting to compare the two (also
+    covering 5 and 20 stage lengths).
+- The IB size and generation rate is tuned to utilize a third of 2000kBs, as
+  Short-Leios targets.
+- NOTE: Other size and timing parameters are mostly the defaults, which need to be updated.