Updates to @actions/artifact package (#367)

* GZip implementation

* Optimizations and cleanup

* Update tests

* More test updates

* Update packages/artifact/src/internal-utils.ts

Co-Authored-By: Josh Gross <joshmgross@github.com>

* Clarification around Upload Paths

* Refactor to make http clients classes

* GZip fixes

* Documentation around compression

* More detailed status information during large uploads

* Pretty format

* Percentage updates without rounding

* Fix edge cases with formatting numbers

* Update packages/artifact/src/internal-utils.ts

Co-Authored-By: Josh Gross <joshmgross@github.com>

* Cleanup

* Small reorg with status reporter

* PR Feedback

* Cleanup + Simplification

* Test Cleanup

* Mock updates

* More cleanup

* Format fixes

* Overhaul to the http-manager

* Fix tests

* Promisify stats

* Documentation around implementation

* Improvements to documentation

* PR Feedback

* Remove Downloading multiple artifacts concurrently

Co-authored-by: Josh Gross <joshmgross@github.com>

packages/artifact/src/internal/__mocks__/config-variables.ts

@@ -0,0 +1,43 @@
+/**
+ *  Mocks default limits for easier testing
+ */
+export function getUploadFileConcurrency(): number {
+  return 1
+}
+
+export function getUploadChunkConcurrency(): number {
+  return 1
+}
+
+export function getUploadChunkSize(): number {
+  return 4 * 1024 * 1024 // 4 MB Chunks
+}
+
+export function getUploadRetryCount(): number {
+  return 1
+}
+
+export function getRetryWaitTimeInMilliseconds(): number {
+  return 1
+}
+
+export function getDownloadFileConcurrency(): number {
+  return 1
+}
+
+/**
+ * Mocks the 'ACTIONS_RUNTIME_TOKEN', 'ACTIONS_RUNTIME_URL' and 'GITHUB_RUN_ID' env variables
+ * that are only available from a node context on the runner. This allows for tests to run
+ * locally without the env variables actually being set
+ */
+export function getRuntimeToken(): string {
+  return 'totally-valid-token'
+}
+
+export function getRuntimeUrl(): string {
+  return 'https://www.example.com/'
+}
+
+export function getWorkFlowRunId(): string {
+  return '15'
+}