chore: add composite metadata bearer auth example

[viglucci]

Motivation:

Provides a basic example for communicating authentication contexts, such as a Bearer auth tokens via composite metadata.

Modifications:

• Adds new example
• Adds NPM scripts in example folder for running example

cd packages/rsocket-examples
npm run start-client-server-composite-metadata-auth-example-server
npm run start-client-server-composite-metadata-auth-example-client

Result:

Server logs:

[2024-10-14 01:29:59] Server bound...
[2024-10-14 01:30:00] Handling EchoService.echo
[2024-10-14 01:30:01] Handling UnknownService.unknown
[2024-10-14 01:30:01] Auth error: Error: Invalid Bearer token provided.
[2024-10-14 01:30:01] Auth error: Error: Missing authentication context.
[2024-10-14 01:30:01] Handling AuthService.whoAmI

Client logs:

[2024-10-14 01:30:01] payload[data: Echo: Hello World; metadata: null]|true
[2024-10-14 01:30:01] EchoService.echo response: Echo: Hello World
[2024-10-14 01:30:01] Expected error: Error: The encoded route was unknown by the server.
[2024-10-14 01:30:01] Expected error: Error: Composite metadata did not include routing information.
[2024-10-14 01:30:01] Expected error: Error: Invalid Bearer token provided.
[2024-10-14 01:30:01] Expected error: Error: Missing authentication context.
[2024-10-14 01:30:01] payload[data: {"firstName":"bob","lastName":"builder"}; metadata: null]|true
[2024-10-14 01:30:01] AuthService.whoAmI response: {"firstName":"bob","lastName":"builder"}