Add support for swift_test and swift_binary (or make the rules configurable)

At the moment there is a hard coded list of rule types that can be used with the bsp plugin in `Sources/SourceKitBazelBSP/RequestHandlers/BuildTargets/TopLevelRuleType.swift`

In my project, I am using swift_binary and swift_test directly from `rules_swift`. It would be nice to either add those, or to make it even more flexible and have an option to configure the mapping of the rules?