Core system for Metrics

[LinasKo]

Description

This PR adds metrics as a standalone supervision module.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How has this change been tested, please provide a testcase or example of how you tested the change?

• At the time of opening the draft PR, I'm till writing tests for it.
• I timed the code, making sure it doesn't add much overhead.
• I'll try using it in a few application, checking that it's pleasant to use.

Any specific deployment considerations

If we'll want pandas to work, we'll need to do pip install 'supervision[metrics]'.

Docs

• Docs updated? What were the changes:

Not updated, but they should be.

[LinasKo]

Here's the status of metrics at the moment:

• mAP is now supported, for masks and boxes
• mAP returns results for all, small, medium, and large objects

To change:

• mAP uses prior IoU function rather than metrics I'll keep it this way during this release.
• IoU metric on masks is much slower, and produces different results
• No plotting function for mAP results
• Not added: mAR
• Untested at scale
• Commits need squishing