Add I/O functions to simplify benchmarking

[HealthyPear]

In the benchmarking notebooks, there are a lot of repeated functions to open and read files generated by protopipe

I will add here also utility functions to read files from ctapipe tools

[codecov]

Codecov Report

Merging #147 (a121e16) into master (52faa69) will decrease coverage by 0.70%.
The diff coverage is 27.90%.

@@            Coverage Diff             @@
##           master     #147      +/-   ##
==========================================
- Coverage   66.84%   66.14%   -0.71%     
==========================================
  Files          23       24       +1     
  Lines        2244     2283      +39     
==========================================
+ Hits         1500     1510      +10     
- Misses        744      773      +29     

Impacted Files	Coverage Δ
protopipe/pipeline/io.py	23.33% <23.33%> (ø)
protopipe/pipeline/utils.py	55.49% <33.33%> (-1.41%)	⬇️
protopipe/pipeline/__init__.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 52faa69...a121e16. Read the comment docs.