cubicweb-calendar #16250954 Remove @import cubicweb.css [validation pending]

Cubicweb.css should not be imported explicitly. The host application should require it if it is required.

Furthermore it breaks the bootstrap version of Cubicweb.

prioritynormal
typeenhancement
done in0.9.0
load0.250
load left0.000
closed by<not specified>
patchremove the @import cubicweb.css [applied]