This patch adds etcd storage implementation. This should be useful in
environments where
- we dont want to depends on a separate, hard to maintain SQL cluster
- we dont want to incur the overhead of talking to kubernetes apiservers
- kubernetes is not available yet, or if kubernetes depends on dex
to perform authentication and the operator would like to remove any
circular dependency if possible.
The previous test doesnt actually testing ListConnectors code. For
example the following pseudocode will pass the test:
```
ListConnectors() { return nil, nil }
```
Instead change to actually fetch and compare list of connectors,
ordering by name
Daniel Dao