Add factory based zap payload logging interceptor

[deepakgupta33]

Feature Request:
We have a use case to extract key-value pairs from the context for the payload logging.

Current state:
The context sent by the grpc framework to the interceptor but there is no hook for payload interceptor user to plug into and be able to decorate the logger with the information in the context object. There are other interceptors which populate the context object.

Solution:
Instead of directly passing on the logger, we create another method that accepts a logger factory. The logger is created only after the context is received with the context object.

[google-cla]

Thanks for your pull request. It looks like this may be your first contribution to a Google open source project (if not, look below for help). Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

📝 Please visit https://cla.developers.google.com/ to sign.

Once you've signed (or fixed any issues), please reply here with @googlebot I signed it! and we'll verify it.

---

What to do if you already signed the CLA

Individual signers

• It's possible we don't have your GitHub username or you're using a different email address on your commit. Check your existing CLA data and verify that your email is set on your git commits.

Corporate signers

• Your company has a Point of Contact who decides which employees are authorized to participate. Ask your POC to be added to the group of authorized contributors. If you don't know who your Point of Contact is, direct the Google project maintainer to go/cla#troubleshoot (Public version).
• The email used to register you as an authorized contributor must be the email used for the Git commit. Check your existing CLA data and verify that your email is set on your git commits.
• The email used to register you as an authorized contributor must also be attached to your GitHub account.

ℹ️ Googlers: Go here for more info.

[deepakgupta33]

@googlebot signed it!