Specify AWS identity to use for signature/request signing

[sid6mathur]

Thanks for the wonderful plugin, it works well! :)

Question: How do I explicitly set the AWS identity to use for request signing?
Scenario: We have 3 AWS users/keys setup on this server (say via profiles in ~/.aws/config) and one of them has the limited ES access that I wish to use with this plugin.

Current behaviour: It appears to use the AWS_SECRET_ACCESS_KEY and AWS_ACCESS_KEY that we set up in the environment (shell) that started the Caddyserver process. That's probably not kosher or scope-limited enough as its a webserver with its many plugins.

Desired behaviour:
a) Use a named profile as listed in ~/.aws/config to use for request signing, configurable as an option in the awses scope block in Caddyfile
b) An alternative is to list the AWS_SECRET_ACCESS_KEY and AWS_ACCESS_KEY explicitly in the awses scope block in Caddyfile, but not sure if that's a security good idea.

Thanks!
Siddharth