Add the discovery client package to ni-apis-python

[mjohanse-emr]

What does this Pull Request accomplish?

• Adds a new namespace package ni.measurementlink.discovery.v1.client that provides the client interface to ni.measurementlink.discovery.v1.proto.
• I copied these files from the measurement-plugin-python repo and made some small edits to fix mypy and unit test errors.
• I copied the discovery client unit tests into this new package.
• I got rid of the deprecated methods in the DiscoveryClient class and updated the unit tests to only use the non-deprecated versions. This includes deleting one unit test that was testing the deprecation warning.
• To avoid a circular dependency, I included the ServiceInfo definition from measurement-plugin-python's measurement client folder in this new discovery client package.

Why should this Pull Request be merged?

Implements AB#3239055

What testing has been done?

Unit tests, mypy, pyright, styleguide.

[github-actions]

Test Results

   66 files  + 20     66 suites  +20   1m 48s ⏱️ + 1m 18s
  180 tests + 36    180 ✅ + 36   0 💤 ± 0  0 ❌ ±0 
1 784 runs  +360  1 774 ✅ +350  10 💤 +10  0 ❌ ±0 

Results for commit df74bb3. ± Comparison against base commit e6ab1b6.

♻️ This comment has been updated with latest results.

[mjohanse-emr]

I'm leaving this review so there are comments on some of the changes I made after copying the files from measurement-plugin-python. Hopefully the comments are useful.

If any of these changes should not be made, please let me know.

[mjohanse-emr]

This package needs to be added to the workflow files to get the checks to run on it. I'm going to wait until @csjall 's PR goes in and I'll add it to the json file.

[jfriedri-ni]

We'll need to update the workflows, too, but it might be simpler to wait for @csjall's #94 to complete first.