consider support for inline buildspec for CodeBuild actions

[mattsb42-aws]

CodeBuild resources can accept a buildspec in two ways: either by specifying a path within the source code to find the buildspec file or by specifying the entire body of the buildspec.

The CodeBuild action interface for pipeformer currently only supports specifying the path to a file.

I'm inclined to put this off until there is demand for it, as IMO the pipeformer config should be as simple as possible and not contain extraneous information.

[mattsb42-aws]

Closing down project: #52