[Enhancement] Update member URL should also restart the embedded etcd run by etcd-wrapper via restart endpoint

[Madhav Bhargava]

Enhancement (What you would like to be added):
etcd-wrapper is going to support a restart HTTP endpoint. See gardener/etcd-wrapper#24.
etcd-backup-restore should now do the following:

1. It should create a new function to ensure that the member peer URL is reflected in the embedded etcd process. This function should do 2 things:
   1. Call member API to update the member URL (we already do this here
   2. Call the newly introduced stop endpoint as per gardener/etcd-wrapper#24.
2. In addition etcd-backup-restore should no longer check the mounted etcd configuration to update the peer URL TLS enablement status via member lease. Instead it should make a member API call. See code.

Motivation (Why is this needed?):
This will ensure that the embedded etcd managed by etcd-wrapper sees the updated member peer URL and will thus prevent a second restart from etcd-druid, thus reducing the complexity in druid.

Approach/Hint to the implement solution (optional):