Automatic merge from submit-queue (batch tested with PRs 57696, 57821, 56317). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Move DefaultMaxEBSVolumes constant into scheduler

**What this PR does / why we need it**:

A constant only used by the scheduler lives in the aws cloudprovider package. Moving the constant into the only package where it is used reduces import bloat. Testing with the dockerized build environment, the kube-scheduler binary went from 61748499 bytes to 47339144 bytes on amd64 with this change.

**Release note**:

```release-note
NONE
```