Add an env var for loading user registered values (dataset, models, clouds) when initializing the Oumi Registry

[taenin]

Description

This PR establishes a new Oumi environment variable, OUMI_EXTRA_DEPS_FILE.
OUMI_EXTRA_DEPS_FILE should be set to a path to a txt file that contains a file path on each line. These file paths should point to *.py files that should be imported before initializing the Oumi Registry.

If unset, only default classes will be loaded.

Example:

OUMI_EXTRA_DEPS_FILE=/oumi/requirements.txt

/oumi/requirements.txt

/path/file1.py
/path2/file2.py
...

/path/file1.py

from oumi.core.registry import register, RegistryType

@register('file_1', RegistryType.CLOUD)
class FileOne:
    pass

/path2/file2.py

from oumi.core.registry import register, RegistryType

@register('file_2', RegistryType.CLOUD)
class FileTwo:
    pass

Related issues

Fixes OPE-745

Before submitting

• This PR only changes documentation. (You can ignore the following checks in that case)
• Did you read the contributor guideline Pull Request guidelines?
• Did you link the issue(s) related to this PR in the section above?
• Did you add / update tests where needed?

Reviewers

At least one review from a member of oumi-ai/oumi-staff is required.

[linear]

OPE-745

[nikg4]

The name OUMI_REGISTRY_REQUIREMENTS is non-intuitive to me.

How about something like OUMI_EXTRA_DEPS, OUMI_CUSTOM_DEPS ?

or with _FILE suffix: OUMI_EXTRA_DEPS_FILE, OUMI_CUSTOM_DEPS_FILE ?

[taenin]

The name OUMI_REGISTRY_REQUIREMENTS is non-intuitive to me.

How about something like OUMI_EXTRA_DEPS, OUMI_CUSTOM_DEPS ?

or with _FILE suffix: OUMI_EXTRA_DEPS_FILE, OUMI_CUSTOM_DEPS_FILE ?

SG, I've switched to using OUMI_EXTRA_DEPS_FILE