Multi-tenant support

[ivancavanaugh]

We need to sent logging to a multi-tenant Loki system from custom build python apps, but multi-tenancy is not supported in the code.

I have already created a fix which is working, but cannot push the branch. Could you provide me with the right WoW for submitting these kind of changes?

[RomanR-dev]

Ive forked and uploaded to pypi my own version, which is also updated in the grafana loki docs
https://github.com/RomanR-dev/python-logging-loki

supporting headers (for tenants).