fix: Allow EnableEmbeddedAsarIntegrityValidation when multiple asars are present in app (#124)

- When an application uses multiple asars (`webapp.asar`, `anything.asar`, etc.), `EnableEmbeddedAsarIntegrityValidation` fuse breaks the application due to not all asars having integrity generated for them. Fixes: #116
- **Also fixes bug** to correctly test `makeUniversalApp no asar mode should shim two different app folders`, (it was not having an asar integrity generated for the shimmed asar)

Functionality added:
- Moves all asar integrity generation to **after** all app assets have been merged/shimmed/copied. This allows other asars that were provided to also be scanned and have asar integrity generated for them.
- Extracted common Integrity logic to a single file `integrity.ts`
- Adds unit test for multi-asar apps

src/file-utils.ts

@@ -45,7 +45,7 @@ export const getAllAppFiles = async (appPath: string): Promise<AppFile[]> => {
           throw e;
         }
       }
-      if (p.includes('app.asar')) {
+      if (p.endsWith('.asar')) {
         fileType = AppFileType.APP_CODE;
       } else if (fileOutput.startsWith(MACHO_PREFIX)) {
         fileType = AppFileType.MACHO;