Add Servile convenience wrapper

Servile is a new convenience wrapper that implements common common configuration
for SERV-based systems so that they don't have to be repeated in every design.

servile.core

@@ -0,0 +1,26 @@
+CAPI=2:
+
+name : ::servile:1.3.0
+
+description: Convenience wrapper for SERV
+
+filesets:
+  rtl:
+    files:
+      - servile/servile_rf_mem_if.v
+      - servile/servile_mux.v
+      - servile/servile_arbiter.v
+      - servile/servile.v
+    file_type: verilogSource
+    depend : [serv]
+
+targets:
+  default:
+    filesets: [rtl]
+
+  lint:
+    filesets: [rtl]
+    flow: lint
+    flow_options:
+      tool: verilator
+    toplevel: servile