[tools] Add README.md file and package.json for local development

Bug: v8:10644
Change-Id: Ic8fa0100a1e276f6c8f7c70b325718d5bdf9123e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3001349
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75569}

tools/README.md

+# TOOLS
+
+This directory contains debugging and investigation tools for V8.
+
+The contents are regularly mirrored to <http://v8.dev/tools>.
+
+## Local Development
+
+For local development you have to start a local webserver under <http://localhost:8000>:
+```
+  cd tools/;
+  npm install;
+  ws;
+```
+
+## Local Symbol Server
+
+The system-analyzer can symbolize profiles for local binaries by running a
+local symbol server
+```
+  cd tools/;
+  ws --stack system-analyzer/lws-middleware.js lws-static cors;
+```
+Note that the local symbol server will run `nm` and `objdump` and has access to
+your files.
\ No newline at end of file

tools/package.json

+{
+  "name": "v8-tools",
+  "version": "1.0.0",
+  "dependencies": {
+    "local-web-server": "^4.2.1"
+  }
+}