Modes in supports

DEPENDS ON: https://github.com/allegro/ralph_assets/pull/414

Rm *modes* (dc,bo) from supports' urls.
Fixed urls generation.
Open attachment views in the same browser's tab (instead of new tab like before) since there is warning about losing data.

@ar4s @quamilek 
change 'sup' to 'support', man
anylize "changing history/support/(?P<support_id>[0-9]+)/$'", to "support/history/(?P<support_id>[0-9]+)/$',