Deduplicate S3 Artifact Uploads in sam package/deploy

### Describe your idea/feature/enhancement

When I run `sam deploy` with many functions sharing the same `CodeUri`, SAM CLI tries to upload the same artifacts many times:

```
Uploading to xxx/ed720a86f3c46571e8dfb831d6axxx 10893967 / 10893967 (100.00%)
File with same data already exists at xxx/ed720a86f3c46571e8dfb831d6axxx, skipping upload
File with same data already exists at xxx/ed720a86f3c46571e8dfb831d6axxx, skipping upload
File with same data already exists at xxx/ed720a86f3c46571e8dfb831d6axxx, skipping upload
File with same data already exists at xxx/ed720a86f3c46571e8dfb831d6axxx, skipping upload
File with same data already exists at xxx/ed720a86f3c46571e8dfb831d6axxx, skipping upload
File with same data already exists at xxx/ed720a86f3c46571e8dfb831d6axxx, skipping upload
File with same data already exists at xxx/ed720a86f3c46571e8dfb831d6axxx, skipping upload
File with same data already exists at xxx/ed720a86f3c46571e8dfb831d6axxx, skipping upload
<... many times>
File with same data already exists at xxx/ed720a86f3c46571e8dfb831d6axxx, skipping upload
File with same data already exists at xxx/ed720a86f3c46571e8dfb831d6axxx, skipping upload
```

Each check/upload takes a few secs and they add up quickly when I have many functions.

### Proposal

Add details of how to add this to the product.

Things to consider:
1. Optimize the upload process so that the artifacts with the same hash (or object key) is only checked and uploaded once.