Send 100 Continue when ready to receive topic downstream

[patuwwy]

What?

🔷 Disable auto sending HTTP 100 Continue

NodeJs auto sends HTTP 100 Continue when it is not strictly handled on server.
We handle it in other way and send when needed so it is sent twice.

https://nodejs.org/api/http.html#event-checkcontinue
https://github.com/nodejs/node/blob/v18.x-staging/lib/_http_server.js#L1110

🔷 Topic downstream queue update

• Require expect: 100-continue header in topic downstream endpoint.
• Send HTTP 100 Continue when request can be processed.

🔷 Refactoring

Move TopicRouter / ServiceDiscovery types to @scramjet/types

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❗ User should wait for HTTP 100 Continue and then start to upload data.

❗ @scramjet/cli / @scramjet/api-client CAN'T listen for 100 Continue as we use node-fetch which doesn't support continue request's event. Data will be sent immediately.

If data are sent with no wait for 100 Continue some bytes can be lost when request is interrupted before we started handling these data.

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Review checks:

These aspects need to be checked by the reviewer:

• Verify and confirm operation (please post a screenshot)
• All STH tests pass
• All Scramjet Cloud Platform tests pass
• Documentation is updated or no changes

[a-tylenda]

verified

[a-tylenda]