Spool.concatenate does not support directory spool

[ahmadtourei]

Description

Currently, Spool.concatenate does not support directory spools but we need to support that as well.

Example

Expected behavior

Versions

• OS [e.g. Ubuntu 20.04]:
• DasCore Version [e.g. 0.0.5]:
• Python Version [e.g. 3.10]:

[d-chambers]

Fixed by #751 (spool index backend). concatenate works on a directory spool.

Verified on dev with three DASDAE files on disk:

out = dc.spool(path).update().concatenate(time=None)
len(out), out[0].shape   # 1, (300, 6000)