CORS support for standalone running instance

[Victor San Kho Lin]

Context:

• A low prior change request: To add direct CORS support for built-in servers for standalone run

Use Case:

• Local dev run with cargo run -p htsget-http-actix to use htsget-rs as backend in Pipeline development and/or Portal integration with IGV.js

Workaround:

• Use Nginx/Haproxy to handle CORS then reverse proxy to htsget-rs servers

Need Changes:

I guess, this should be quick -- 2 parts in there:

• actix_cors crate for actix-web for Ticket server
• activate tower_http::cors feature in tower/axum for built-in storage streaming server

[Marko Malenic]

Closed via #119.