ETCD support for DCS

[AnisTigrini]

Hi There, noticed there is an environment variable to inject "etcd_host" but there are none in the repo for usernames and password. Could create a PR for that to add them to the operator configmap ?
Could enable etcd3 as well since there are no env variables for v3 (supported by Patroni).
Let me know what you guys think.

[thangamani-arun]

I agree with @AnisTigrini .
Also consider adding support for major key/value stores like consul etc

[FxKu]

More config options are fine with me to support more Patroni features. Not all at once maybe 😃

[AnisTigrini]

here you go @FxKu, let me know for anything.
PR Link : #1849

[gc-jro]

This would be a really helpful feature.

[0x442E472E]

Hello, is this feature still coming? Supporting a newer ETCD would be beneficial for our use case.