Respond to pinning RPCs as soon as possible

(instead of waiting until you've read an unbounded number
of pin logs while queries back up in memory)

Also replace instances of 'publicKey' with 'safeKey' or 'unsafeKey'
to clearly and correctly indicate their format.

lib/rpc.js

@@ -2,7 +2,6 @@
 const nThen = require("nthen");
 
 const Util = require("./common-util");
-const mkEvent = Util.mkEvent;
 
 const Core = require("./commands/core");
 const Admin = require("./commands/admin-rpc");
@@ -219,9 +218,14 @@ RPC.create = function (config, cb) {
         Sessions: {},
         paths: {},
         msgStore: config.store,
+
         pinStore: undefined,
         pinnedPads: {},
-        evPinnedPadsReady: mkEvent(true),
+        pinsLoaded: false,
+        pendingPinInquiries: {},
+        pendingUnpins: {},
+        pinWorkers: 5,
+
         limits: {},
         admins: [],
         Log: Log,