feature idea: split https signing into lib

[benjamin-asdf]

Use case:
Make an https request as iam user. For example to invoke a lambda with the new lambda-url.
There is https://github.com/sharetribe/aws-sig4
cons:

• depends on http-clj
• depends on classes that are not in babashka (which is a big part of my aws-api usage)

Just an idea.

[fogus]

Pulling things apart has been on the agenda for a while and designs are proceeding (albeit slowly). I think that a cut point at signing seems reasonable. More thought needed of course. Thank you for your report.