Update the version of node in this repo to at least 20.5

[jbjonesjr]

Update the Node.js version to at least 20.5 in the repository.

• package.json: Update the node version in the engines field to >=20.5.0.
• src/app/package.json: Update the node version in the engines field to >=20.5.0.
• src/rtl-publish/package.json: Update the node version in the engines field to >=20.5.0.
• src/server/package.json: Add the engines field with node version >=20.5.0.
• src/services/package.json: Add the engines field with node version >=20.5.0.
• .devcontainer/devcontainer.json: Update the Docker image to mcr.microsoft.com/devcontainers/typescript-node:0-20.

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