Refactor some of the types used by FBLogger into Logger

Summary:
^

This change aims to extract some bits and pieces that are not specific to FBLogger and could be used by other Logger implementations.

Reviewed By: passy

Differential Revision: D36473286

fbshipit-source-id: 57f02d132673dbac97384da4dca51bf3e6fb8738

desktop/flipper-common/src/index.tsx

@@ -9,6 +9,10 @@
 
 export {
   Logger,
+  LoggerExtractError,
+  LoggerFormat,
+  LoggerInfo,
+  LoggerPerformanceEntry,
   LoggerTrackType,
   LoggerTypes,
   LoggerArgs,