Add max_time which is the time when hit reaches its maximum

[dachengx]

What is the problem / what does the code in this PR do

Close: XENONnT/straxen#1360

Can you briefly describe how it works?

Can you give a minimal working example (or illustrate with a figure)?

Please include the following if applicable:

• Update the docstring(s)
• Update the documentation
• Tests to check the (new) code is working as desired.
• Does it solve one of the open issues on github?

Please make sure that all automated tests have passed before asking for a review (you can save the PR as a draft otherwise).

[coveralls]

coverage: 90.128% (+0.008%) from 90.12%
when pulling 9695504 on save_max_time
into f9dd6c3 on master.