Update nodejs module to use workspaces instead of Lerna

[martinkuba]

The nodejs sub-project is currently using Lerna, which is a tool for managing multiple Node packages in a single repository. The bootstrap/install process that Lerna was used for in the past are now possible with npm workspaces.

Lerna has already deprecated its bootstrap command/mechanism in favor of workspaces. This is the reason that Lerna cannot be currently upgraded (see https://github.com/open-telemetry/opentelemetry-lambda/pull/1085) - the Node lambda package is calling lerna bootstrap during install, and it also runs on Node 14, which is not supported by latest Lerna version.

I propose that we

• change to use npm workspaces and remove lerna bootstrap
• upgrade lerna
• run the Node CI workflow on a newer version of Node