Removing path and line number from warnings. (#447)
Removing path and line number from warnings. (#447)

* Removing path and line number from warnings.

* Declutters the warning message so the message is easier to see
* Removes the `warnings.warn(message)` from the message as well.
* Difference between old and new shown below:

Previous:
```
/Users/DevinPetersohn/software_builds/modin/modin/error_message.py:32: UserWarning: `cov` defaulting to pandas implementation.
To request implementation, send an email to feature_requests@modin.org.
  warnings.warn(message)
```

This commit:
```
WARN: `cov` defaulting to pandas implementation.
To request implementation, send an email to feature_requests@modin.org.
```

* Adding warning type to the message instead of "WARN"

* Code reorganization

modin-project/modin,modin-project/modin