Support single file linting mode that does not recurse through imported files

[jvsqzj]

To interface reporting of syntax and/or style errors for single files with other tools, a "direct" mode for the CLI client should be implemented.

This mode will not recurse through imported files in a given DML source file, and will limit its parsing and analysis to the scope of a single file.

Currently, the use of the CLI tool will attempt to recurse through every import.

Intention is to cover these three points:

1. For "direct" mode, DeviceAnalysis jobs should not run, and the DFA CLI client should not wait for their result
2. In this mode, IsolatedAnalysis job requests from the ActionContext should not be sent to the server loop AnalysisStorage
3. To properly suppress attempts to resolve imports of files in this mode, the import resolution and mapping logic needs to be modified. Many aspects of current implementation will need consideration to do this correctly, like dependency ordering, import invalidation, and path mapping.

[jvsqzj]

Closing with merge of #34