appointment can be removed, but only when not atached to visit and with SCHEDULED status

Closes #150

See merge request NCER-PD/scheduling-system!95

list of appointments contains information about availabilities

Closes #143

See merge request NCER-PD/scheduling-system!94

validation of nd number added

Closes #148

See merge request NCER-PD/scheduling-system!93

when exporting there is artifitial column that marks dropped out subjects

Closes #156

See merge request NCER-PD/scheduling-system!92

subject contain resign reason field (obligatory when marking subject as resigned)

Closes #155

See merge request NCER-PD/scheduling-system!91

resolution improved

Closes #168

See merge request NCER-PD/scheduling-system!90

edit button in list of subjects is standard 'a' tag

Closes #149

See merge request NCER-PD/scheduling-system!89

list of countries is provided as predefined list

Closes #170

See merge request NCER-PD/scheduling-system!88

in daily planning user can schedule non-subject related appointments

Closes #160

See merge request NCER-PD/scheduling-system!87

Resolve "follow up visits should be based on visit one date"

Closes #169

See merge request NCER-PD/scheduling-system!86

subject list contain list of visits

Closes #140

See merge request NCER-PD/scheduling-system!85

Resolve "possibility to remove worker"

Closes #151

See merge request NCER-PD/scheduling-system!84

Merge branch '167-daily-planning-should-use-abbreviation-in-the-title-of-the-appointment-type-in-calendar-view' into 'master'

fix on disappearing title when removing appointment from daily planning

Closes #167

See merge request !83