Log request body

[achave11-ucsc]

https://github.com/DataBiosphere/azul-private/issues/128#issuecomment-2224116914

@hannes-ucsc: "Don't file partial PR against #128 but instead a normal PR against this issue."

[edit, @achave11-ucsc, updated specification]

[achave11-ucsc]

@hannes-ucsc: "I originally specified this as follows:"

Assignee to implement a partial PR that adds logging of the request body by Chalice middleware, similar to how we log the response body. With AZUL_DEBUG set to 0 or 1, the length and the first 1024 bytes of the request body should be logged. With AZUL_DEBUG set to 2, the length of the body, and the full body should be logged.

Once the logging of the request body length has been deployed for a couple of months, we can resume the original plan.

@hannes-ucsc: "Doing PR review, I noticed that this is inconsistent with the logging of response bodies. Here is the updated specification: At AZUL_DEBUG=0, only log the length of the request and response bodies. At AZUL_DEBUG=1 log the length and the first 1024 bytes of these bodies. At AZUL_DEBUG=2 log the length and the complete body."