Update workflows to use self hosted runners

[nathanklick]

Description

We need to update the .github/workflows/nodejs.yml workflow to use the ephemeral self-hosted runners which are now configured on this repository. Additionally, we should add a workflow dispatch trigger to improve ease of testing.

Requirements

• Change the runs-on specification to the following stanza:
  • runs-on: [self-hosted, hardhat, hethers, standard, ephemeral]
• Add a workflow_dispatch trigger to the on declaration
• Update the following actions to use the v3 version:
  • actions/setup-node
  • actions/checkout
• Enable NodeJS caching support