Support SESSION_TOKEN for SES (and other aws apis)

[jhogendorn]

:bulb: Session Token Support

I'm looking into the use of apprise in CICD tooling. In our environment we don't allow long lived credentials of any kind. Because apprise manually builds a call to the aws rest api, we cant rely on normal sdk behaviour (machine roles, environment vars etc). So support for Session Tokens in the api request is needed so we can utilise short lived credentials. In our case these will come from vault aws secrets engine using assumed_role or session_token.

According to AWS docs Calling against the api with short lived credentials just requires the addition of an extra header X-Amz-Security-Token. This header needs to be in the canonical headers of the signature

In the case of SES, I think it just needs to be added to this array?

The session_token would need to be provided to apprise, but I'm not sure what the convention is for an optional input like this, whether it would need to be part of the url, provided as an argument to the cli, present as an environment variable etc. (Hence why this isnt a PR from me at this stage)

:hammer: Breaking Feature

This wouldnt break any current implementation afaik.

[caronc]

It would likely become part of the URL... something like sns://{SessionKey}@{AccessKeyID}/{AccessKeySecret}/{Region}/+{PhoneNo}

[jhogendorn]

Sure, sounds good. Is this something thats fairly straight forward to do? I'm happy to look into making a PR but if its something you can knock out fast thats probably more efficient.