astakos: Do not require total members number in projects form

set to infinite if no value is set to mimic api behaviour
astakos: Projects display improvements

- Replace "users" to "members" in labels in project form/detail views
- Fix ordering of per member/total resources display
- Remove "cancel" action in create/modify project summary view
- Differentiate project modification heading (append "modification" suffix)
- Reword "base project" to "system project". User "[system]" prefix with
  user email address and name to display base projects to admins.
- Hide details/membership sections in base project modificatation/details views.
astakos: Display resource usage in project detail view