feat(JS lib): add a client JS lib for the Communicator

similar to trame-client js-api, trame-iframe js-api provides an agnostic library
that can be installed in a regular JS project.
trame-iframe js-api could be installed in a host application (could be
react/streamlit/vue/... based) to proxy the trame API calls through the
iframe to the Communicator and the trame application.
The goal is to replicate the trame-client js-api features to make it
transparent to the consumer code.
API:
- trame.state.set
- trame.state.update
- trame.state.watch
- trame.trigger

This is still possible to directly interact with the Communicator from
an host application by manually sending/listening to events.

js-lib/.eslintrc.cjs

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+/* eslint-env node */
+require("@rushstack/eslint-patch/modern-module-resolution");
+
+module.exports = {
+  root: true,
+  extends: [
+    "eslint:recommended",
+    "@vue/eslint-config-prettier",
+  ],
+  env : {
+    browser : true,
+    es6 : true,
+  },
+  rules : {
+    "no-unused-vars" : 2,
+    "no-undef" : 2
+  },
+  parserOptions: {
+    sourceType: "module",
+    ecmaVersion: "latest",
+  },
+};

js-lib/.gitignore

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+dist

js-lib/LICENSE

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+Apache Software License 2.0
+
+Copyright (c) 2024, Kitware Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

js-lib/README.md

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+// const trame = new Trame({ iframe });
+// await trame.connect({ application: 'trame' });
+
+// State handing
+trame.state.set("a", 5);
+console.log(trame.state.get("b"));
+trame.state.update({
+    a: 1,
+    b: 2,
+}); 
+
+// Method call on Python
+const result = await trame.trigger("name", [arg_0, arg_1], { kwarg_0: 1, kwarg_1: 2 });
+
+// TODO - state watching
+trame.state.watch(["a"], (a) => {
+    console.log(`a changed to ${a}`);
+})