Array API: port straightforward functions in `shells`

[paddyroddy]

Is Your Feature Request Related to a Problem? Please Describe

• [ ] shells.RadialWindow
• [ ] shells.tophat_windows
• [ ] shells.linear_windows
• [ ] shells.cubic_windows
• [ ] shells.restrict
• [ ] shells.partition
• [ ] shells.partition_lstsq
• [ ] shells.partition_nnls
• [ ] shells.partition_restrict
• [ ] shells.redshift_grid
• [ ] shells.combine

Describe the Solution You'd Like

No response

Describe Alternatives You've Considered

No response

Additional Context

No response

[paddyroddy]

Blocked by #273