Add isGhes gate and refactor to clean up circular dependencies

src/internal/blob/download-cache.ts

@@ -6,7 +6,7 @@ import {
   BlobDownloadOptions
 } from '@azure/storage-blob'
 
-export async function DownloadCacheFile(
+export async function downloadCacheFile(
   signedUploadURL: string,
   archivePath: string
 ): Promise<{}> {

src/internal/blob/upload-cache.ts

@@ -5,7 +5,7 @@ import {
   BlockBlobParallelUploadOptions
 } from '@azure/storage-blob'
 
-export async function UploadCacheFile(
+export async function uploadCacheFile(
   signedUploadURL: string,
   archivePath: string
 ): Promise<{}> {