Merge `cloudformation.json` and `cloudformation-no-trail.json`

cloudformation.json and cloudformation-no-trail.json are largely repetitions of each other, the former simply creates some resources that latter does not. Turn the creation of cloudtrail resources into a CFT boolean parameter, then predicate creation of those resources on a conditional that is determined by that parameter.

This will avoid drift between the two files. There already is a little. It's minor right now, but it is likely to grow in the future.

Here's that drift (spelling of the word "lambda"):

cloudwatch2humio/cloudformation.json

Line 64 in 93eb520

    
           "Description" : "A comma separated list of subnet ids used by the VPC configuration that the ingester lamda functions will be deployed into. Only required if VPC is enabled."

cloudwatch2humio/cloudformation-no-trail.json

Line 64 in 93eb520

    
           "Description" : "A comma separated list of subnet ids used by the VPC configuration that the ingester lambda functions will be deployed into. Only required if VPC is enabled."

This issue has been solved in the new release.