New workflow to deploy the lambda function

[kov]

Build the lambda function, package it as expected by AWS lambda, then update it on AWS.

For now this is only triggered manually, so that the update can be performed only when it makes sense to the developers. In the future we can make a release being tagged trigger this workflow.

[obbardc]

we should probably explain what secrets need to be added too

[kov]

we should probably explain what secrets need to be added too

explain where? I can add it to the doc on deploying the lambda function I guess, after it has been validated