Flint: Provide axis markers
This MR generalize the concept of motor marker used in Flint to replace it by an axis marker:
- This can be used to mark a location of an axis (as it was with motor marker)
- Many markers can be created in a single plot (which was not the case for motor markers)
-
plot.update_motor_marker(channel_name, position, text)
was removed -
plot.update_axis_marker(unique_name, channel_name, position, text)
was added