close #59

Should be reuse for tomoh2nx

add more information and create section

now contains `general`, `keys`, `entries and titles`, `frame type` and `extra params` sections.

Also contains input and output file, log level....

[_insert_frame_data] raise an error if slice 'step' value different than 1 or None is provided and we don't want to do dataselection

[utils][_insert_frame_data] VirtualSource creation: create the adapted selection. (can be a FancySelection when needed.)

- this is not handling slice 'step' different than None or 1
- /close #40

- add option `--embed-data` to embed data in the file. False by default
- add_dark_flat_nx_file: turn default value to False

Allow to split treatment and gain in readibility of the code.

[converter] refactoring: split the edf and the hdf5 convert. Add classes for each possible acquisition type for hdf5

# Conflicts:
#	nxtomomill/converter.py

This reverts commit 6ce70a7f.

/close #3277

This reverts merge request !34

[utils][_insert_frame_data] fix virtual dataset creation. Cannot use SapceID.shape but should use bounds

This reverts commit 03cf6873.

This reverts commit 6c494438.

This reverts commit fe9030b7.