Add importlib_metadata dependency for ocs-agent-cli

[BrianJKoopman]

Description

Adds importlib_metadata as a dependency for python versions below 3.10, as used in ocs-agent-cli.

Motivation and Context

Ran into this missing dependency on an older system with Python 3.8.

How Has This Been Tested?

Installed in a clean python3.8 and python 3.10 environment to check the python version dependent install, and ran ocs-agent-cli to confirm missing module error went away.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.