Docs: broken links to MLBazaar/mlstars primitive JSON files (repo appears removed)

[karishmavelisetty]

Seven primitive reference pages in the docs link to primitive JSON files in MLBazaar/mlstars, and all of them return 404. The MLBazaar/mlstars repository itself appears to be unavailable — https://github.com/MLBazaar/mlstars returns 404, and I couldn't find it under an obvious rename (MLBazaar/MLStars, sintel-dev/mlstars also 404), so this isn't just a master→main branch rename.

Affected docs pages:

• docs/user_guides/primitives_pipelines/primitives/SimpleImputer.rst
• docs/user_guides/primitives_pipelines/primitives/MinMaxScaler.rst
• docs/user_guides/primitives_pipelines/primitives/LSTMTimeSeriesRegressor.rst
• docs/user_guides/primitives_pipelines/primitives/time_segments_aggregate.rst
• docs/user_guides/primitives_pipelines/primitives/intervals_to_mask.rst
• docs/user_guides/primitives_pipelines/primitives/arima.rst
• docs/user_guides/primitives_pipelines/primitives/rolling_window_sequences.rst

Dead link pattern: https://github.com/MLBazaar/mlstars/blob/master/mlstars/primitives/<primitive>.json

Could you confirm where the mlstars primitive definitions now live? Once the correct location is known, I'm happy to open a PR updating all seven links.