etcd performance settings

[ChrisRx]

There are etcd settings that should be provided as tunables in the case they are required. The biggest one in particular is QuoteBackendBytes which ends up allowing the user to override etcd's initial 2GB storage limit.

[ChrisRx]

etcd-io/etcd#11946

This would be a valuable option to use for ephemeral usages of e2d where disk performance is more important than durability/safety.