Add telemetry and option to disable

[kylecarbs]

Enables telemetry with default VS Code events being tracked.

Adds --disable-telemetry flag and DISABLE_TELEMETRY env variable making an extremely easy opt-out.

[illiapoplawski]

When you included the changes from pr 422 the change that I mentioned didn't get added to this pr.

Just noticed doc/self-hosted/index.md also mentions the code-server -h help option at bottom.

Use code-server -h or code-server --help to view the usage for the cli. This is also shown at the beginning of this section.

should read:

Use code-server --help to view the usage for the cli. This is also shown at the beginning of this section.

[kylecarbs]

@illiapoplawski fixed!

[NHollmann]

It would be nice if there were more details on telemetry. I know, I can disable it, but if I knew what exactly is sent I would consider turning it back on. 🤔

[deansheather]

@NHollmann:

• Machine ID (generated by code-server and cached if there's no OS machine ID)
• CPU core count, model
• Memory usage, total memory
• Shell (bash, zsh, etc.)
• OS release and arch

Along with any information VSCode telemetry sends by default which is documented thoroughly in their source: microsoft/vscode#34997.