Use SOM peaklets classification by default

[dachengx]

Before you submit this PR: make sure to put all operations-related information in a wiki-note, a PR should be about code and is publicly accessible

Depends on #1472

What does the code in this PR do / what does it improve?

SIGNIFICANT CHANGE
BREAKING CHANGE

Can you briefly describe how it works?

Use SOM classification (https://xe1t-wiki.lngs.infn.it/doku.php?id=xenon:xenonnt:lsanchez:som_summary_note) by default.

Following #1269 and #1300.

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?

Notes on testing

• Until the automated tests pass, please mark the PR as a draft.
• On the XENONnT fork we test with database access, on private forks there is no database access for security considerations.

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[sebvetter]

Do we want the default plugins to be called pluginSOM? E.g. straxen.PeaksSOM, straxen.PeakBasicsSOM,

[dachengx]

Do we want the default plugins to be called pluginSOM? E.g. straxen.PeaksSOM, straxen.PeakBasicsSOM,

I do not like it, either. Any suggestions? :)

[sebvetter]

What is the problem with simply naming the class Peaks, or rather overwriting the old Peaks plugin with the contents of the PeaksSOM plugin? The old code will be preserved in older straxen versions. Will there still be some plugins after this PR that use the non-SOM versions?

[dachengx]

What is the problem with simply naming the class Peaks, or rather overwriting the old Peaks plugin with the contents of the PeaksSOM plugin? The old code will be preserved in older straxen versions. Will there still be some plugins after this PR that use the non-SOM versions?

E.g, PeakletClassificationSOM is inherited from PeakletClassification so we have to keep PeakletClassification.

But maybe rename PeakletClassification to something else?

[coveralls]

coverage: 89.792% (+1.1%) from 88.685%
when pulling 2bb7e68 on som_default
into 28240ff on master.