Patch image key

Propose option to modify image_key and image_key_control from:

• a function: utils.change_image_key_control
• command line: from patch-nx

INFO

example of usage:

# force frames 26 and 27 to be dark
nxtomomill patch-nx --update-to-dark 26:28 simple_case.h5 entry
# force frames 10, 13, 16 and 19 to be flatfield
nxtomomill patch-nx --update-to-flat 10:20:3 simple_case.h5 entry
# force frame 0, 1 and to 4 to be projections
nxtomomill patch-nx --update-to-proj 0,1,4 simple_case.h5 entry
# force first frame to be alignment projection
nxtomomill patch-nx --update-to-alignment 0 simple_case.h5 entry
# force all frames to be invalid
nxtomomill patch-nx --invalid-frames : simple_case.h5 entry