Employ resiliency patterns for external service calls

[nscuro]

In the context of #124, we should ensure that all HTTP clients are using resiliency patterns to ensure throughput remains acceptable.

In general, we want to ensure that stream threads are not blocked for longer than necessary.

• Ensure all clients use sane timeouts (a request taking longer than a few seconds is perhaps not worth waiting for)
• Consider using circuit breakers to not make the situation worse under high load: https://resilience4j.readme.io/docs/circuitbreaker
• Ensure requests are retried (#124)

[sahibamittal]

I can take this up. 👍🏼

[nscuro]

I think we covered the vulnerability analyzer side of things, but we still need to address the repo meta analyzer and notification publisher services.