Add DeviceManager as alternative to make_all_devices

[tpoliaw]

See #1574 for some context

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.13%. Comparing base (f50aaaa) to head (81197bd).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1549      +/-   ##
==========================================
+ Coverage   99.09%   99.13%   +0.03%     
==========================================
  Files         277      278       +1     
  Lines       10209    10478     +269     
==========================================
+ Hits        10117    10387     +270     
+ Misses         92       91       -1     

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[DominicOram]

Thanks, minor stuff mostly. However, I think the typing for v1 is broken if I run eiger = i03.fastcs_eiger.build(mock=True) the type system picks up that eiger is an EigerDetector if I run eiger = i03.eiger.build(mock=True) it thinks it's a V1@v1_init. Not that big a deal as we only have the one v1 device.

[rtuck99]

Approved, you can make the change with the LazyFixtures if you want but I'm not terribly fussed either way

[tpoliaw]

However, I think the typing for v1 is broken

Should be fixed

I'm happy if Rob is happy