Enable optional Telemetry integration via posthog (#190)

README.md

server/endpoints/chat.js

server/endpoints/system.js

server/endpoints/utils.js

server/endpoints/workspaces.js

server/index.js

server/models/documents.js

server/models/systemSettings.js

server/models/telemetry.js

server/package.json

server/utils/database/index.js

server/yarn.lock