Fix broken telescope id string, Fixes #1058

[kosack]

• telescope names are now normalized to TYPE_OPTICS_CAMERA (usable as an output file or group name)
• SubarrayDescription.get_tel_ids_for_type() was broken due to the previous name change, this fixes it
• added a lot of unit tests to prevent regression
• added a function and property to map telescope IDs to telescope indices (useful for creating things like trigger patterns or packing telescope data)

[codecov]

Codecov Report

Merging #1069 into master will increase coverage by 0.11%.
The diff coverage is 97.58%.

@@            Coverage Diff             @@
##           master    #1069      +/-   ##
==========================================
+ Coverage   83.44%   83.56%   +0.11%     
==========================================
  Files         181      181              
  Lines       10439    10494      +55     
==========================================
+ Hits         8711     8769      +58     
+ Misses       1728     1725       -3

Impacted Files	Coverage Δ
ctapipe/instrument/tests/test_camera.py	100% <100%> (ø)	⬆️
ctapipe/instrument/tests/test_subarray.py	100% <100%> (+2.77%)	⬆️
ctapipe/instrument/guess.py	100% <100%> (ø)	⬆️
ctapipe/io/hessioeventsource.py	92.8% <100%> (ø)	⬆️
ctapipe/instrument/tests/test_telescope.py	100% <100%> (ø)	⬆️
ctapipe/io/simteleventsource.py	98.46% <100%> (ø)	⬆️
ctapipe/instrument/tests/test_optics.py	100% <100%> (ø)	⬆️
ctapipe/image/muon/muon_reco_functions.py	66.66% <100%> (ø)	⬆️
ctapipe/instrument/telescope.py	96% <90.9%> (+0.54%)	⬆️
ctapipe/instrument/optics.py	94.28% <92.3%> (+2.85%)	⬆️
... and 2 more

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