Feature request: Support dotnet lambda container builds

### Describe your idea/feature/enhancement

All other language run-times support the `--use-container` option for `sam build` except dotnet runtimes. With the addition of [build images for dotnet](https://github.com/aws/aws-sam-build-images/pull/25) it should now be possible to do this.

I've tested this with a [quick hack here](https://github.com/aws/aws-sam-cli/commit/34a3fd8859759ed7e8bec568276fee97bc2b5b03) and it appears to work. I was able to successfully build and publish a `dotnet6` runtime lambda via the following commands:

```bash
sam build -u
sam deploy --config-file samconfig.toml
```

However, I am guessing the change from read-only to read-write for the manifest dir is not ideal.

### Proposal

Add support for dotnet lambda builds via docker containers to align with other runtime supported builds.

Things to consider:
1. May require updates to the docker build logic to support how it is handled via dotnet