Support operator to inject sidecar?

[caibirdme]

Do we have any plan to support k8s operator to inject vector as a sidecar container? We want to widely deploy vector in our system, but here's the problem we met:

1. we don't use stdout/stderr to log, we use file
2. It's nearly an impossible task to write a series new SDKs(go java rust cpp) for all services that can buffer logs and send data to the centralized vector
3. Even we manage to write these sdks, it'd be a very long term to have different teams use these new sdks in their production

Maybe the most non-intrusive and easiest way is that:

1. people still write log to local files
2. people tell "log system" where their log files are and the url of the centralized vector service by ENVIRONMENT, something like:

   env:
   - key: LOG_FILE
   value: /a/b-*.log;/c/d.log
   - key: LOG_SERVICE
   value: example.com:6788

3. Operator inject vector container as a sidecar for every pod, and vector instance bootstrap with these env params

   So, as the infra team, we just need to install a vector operator on k8s cluster. And as for other business teams, they just need to do no more than 4 lines change for their deployment.yaml file.

[spencergilbert]

At this time it's not on our roadmap, but it has been discussed again recently.

Closing as a duplicate of: https://github.com/vectordotdev/vector/issues/768