[wip] adding message signing functionality

Problem is this:

    Uncaught ReferenceError: require is not defined
        <anonymous> moz-extension://b4685fc7-232c-44d9-b653-f51b7c7ea868/dist/jex_include/local-vdk_aecrypt-0.1.0/dist/jex_include/local-blakejs-1.2.1/dist/index.js:1
    index.js:1:13

The issue is that blakejs is written for node and needs to be modified to work
in a browser.

Next task is doing that, but did a ton of work so taking a break

libs/vdk_aecrypt/jex.eterms

@@ -0,0 +1,6 @@
+{type, library}.
+{realm, local}.
+{name, vdk_aecrypt}.
+{version, "0.1.0"}.
+{deps, ["local-blakejs-1.2.1",
+        "local-vdk_binary-0.1.0"]}.