Entry point mainfile binary header

Even if I define mainfile_binary_header directly in the parser entry point, this is not picked up when building the parsers in nomad/parsing/parsers.py. Essentially,

enabled_entry_points = config.plugins.entry_points.filtered_values()

returns the entry point without mainfile_binary_header.

Can you please confirm this @himanel1 ? Would be great if a solution if found soon as some parsers require it.