Upgrade to Node JS v20

[Nana-EC]

Problem

The relay currently uses node version 18 which has an end of life at the end of April 2025

Solution

Upgrade to the latest LTS version which is currently v20

• Update reference of v18 to latest LTS v20
• Run complete acceptance test suite on HTTP server
• Run complete acceptance test suite on WS server
• Confirm CI jobs run
• Run DApp Tests
• Run Smart contract repo test suites
• Run perf tests and measure an deltas
• Deploy an alpha and confirm in previewnet

Alternatives

Make a consideration for v22.5.1 as it was recently identified as a pinned version of nodejs for the ethers library. Something to check