Expose some etcd configuration in the spec

**What would you like to be added**:
Add the ability to expose etcd options, like increasing the etcd DB size by modifying the `ETCD_QUOTA_BACKEND_BYTES` variable in the `/etc/etcd/etcd.env` file.

**Why is this needed**:
Modifying this file requires modifying each etcd node, restarting the server, and doing a compact and defrag for changes to be reflected. This could be automated through the bootstrapping phase.

Workarounds:
* make the change manually
* modify the template prior to bootstrapping cluster, or upgrading the template in the spec with this change baked in as part of automation through image-builder
* look into why DB is taking so much space as the default recommended is usually 2GB, so should look into what is taking up space by following this: https://etcd.io/blog/2023/how_to_debug_large_db_size_issue/