Unpin node versions in CI

This PR makes the following changes:

Changes node versions across teraslice to use major versions of node as a valid node version
- This is because the env variable NODE_VERSION used in e2e is tied to a valid tag in terascope/node-base
Added workflow_dispatch to the daily-docker-cache.yml to allow for manual workflow trigger
Added check-latest-node-version.sh script for devs to find out which node version is currently used in the base image
- This is a convenience utility script that could be used somewhere else later to pop up a warning.
Bumped @terascope/scripts from v0.81.2 to v0.81.3
Updated docs to explain how tagging works in the base image repo

Ref to issue #3683

terascope / teraslice