[MRG+1] Unify read annotations

[massich]

Fixes #5670

Things to do:

• migrate the calls of:
  • brainstorm
  • brainvision
  • EDF
  • fif
  • eeglab
• Depreacate read_annotations_eeglab since it was in 0.16
  rst - Add function :func:`mne.io.read_annotations_eeglab` to allow loading annotations from EEGLAB files, by `Alex Gramfort`_`

[agramfort]

I would remove the _caller

[massich]

I'm not sure. What I think it should be done is unify them all.
I would propose to remove all the Annotation construction of the readers and delegate it here to mne.annotations.read_annotations. In this manner, all readers should have a function _read_annotations_XX (or parse or whatever) which does know about the file format and returns valid onsets, duration, description and orig_time. And remove the import Annotations.

However, this would be easier when read_annotations_eeglab is no longer there, and the synthesis of the stim channel is removed from the edf reader.

[massich]

but meanwhile, I'll just remove the callers.

[agramfort]

Yes let’s remove it

[codecov]

Codecov Report

Merging #5695 into master will decrease coverage by <.01%.
The diff coverage is 96.22%.

@@            Coverage Diff             @@
##           master    #5695      +/-   ##
==========================================
- Coverage   88.51%   88.51%   -0.01%     
==========================================
  Files         369      369              
  Lines       69136    69148      +12     
  Branches    11645    11651       +6     
==========================================
+ Hits        61193    61203      +10     
- Misses       5089     5090       +1     
- Partials     2854     2855       +1

[massich]

If you guys think that:

• the RFC, are not important
• CIs are green
• Two people +1

then feel free to merge.

[larsoner]

CIs are not happy, let me know when they are and I can take a look

[larsoner]

Marking this for 0.17

[larsoner]

Is the TODO list at the top outdated, as there are things incomplete in the list