feat: elastic bridge - interfaces

[manuel-gamma]

Add ElasticsearchClientInterface & ElasticsearchServiceInterface for more flexibility (ex: service decoration).

[manuel-gamma]

Hi @paullla can you help me please ? Scrutinizer can't prepare the container, how can i resolve this ?

[paullla]

hey @manuel-gamma , it was a temporary error, I rerun it and it's all good now

[manuel-gamma]

Hello,

Any feedbacks on this PR ?

Thanks

[paullla]

Hi @manuel-gamma, first of all, apologies for the long silence on this, and thank you for the patience (and the pings).
I've reviewed the PR and I like it. Typing consumers against ElasticsearchClientInterface/ElasticsearchServiceInterface instead of the concrete classes is exactly the direction we're heading: we're planning a pluggable storage layer for 2.0, with Elasticsearch as the first backend, and these interfaces are a natural first step toward it.
CI was broken for all PRs until today. I've updated your branch with the merged master and the test suite passes. Merging, thanks a lot for contributing!