* Add config.proto
* Make protos
* Add ConfigurableSource implementation
* Parse config protoyaml into configured sources
* Refactor setting postman keywords into a helper method on the engine
* Add scan subcommand and plumb it all together
* Refactor ConfigurableSource to ConfiguredSource
* Export AhoCorasickCoreKeywords and return the set
* Disallow source configurations for non-scan subcommands
* Fix stdin scan compilation errors
* Rename command to multi-scan
* Add config file documentation
* Add more documentation for ConfiguredSource
* Replace initFunc closure with an embedded anonymous struct
* Assign directly to refs
* Fix typo