SymbolServer: Add symbolication service for out-of-process ELF parsing

This patch adds SymbolServer, a service daemon that provides
symbolication of ELF binaries. It has a very simple IPC API at the
moment that only turns addresses into symbol names.

This can be used to implement symbolication without having to do
in-process ELF parsing yourself. :^)

Userland/Services/SymbolServer/SymbolClient.ipc

@@ -0,0 +1,4 @@
+endpoint SymbolClient = 4541511
+{
+    Dummy() =|
+}