:sparkles: Add a logout button when not authorized to access a page in Admin
:sparkles: Add a logout button when not authorized to access a page in Admin

Otherwise if the user cannot access any page it needs to clear the
cache to be able to logout and login again

dimayakovlev/grav-plugin-admin,Vivalldi/grav-plugin-admin,Sommerregen/grav-plugin-admin,getgrav/grav-plugin-admin,dimayakovlev/grav-plugin-admin,Sommerregen/grav-plugin-admin,Vivalldi/grav-plugin-admin,getgrav/grav-plugin-admin,Sommerregen/grav-plugin-admin,Sommerregen/grav-plugin-admin,dimayakovlev/grav-plugin-admin,getgrav/grav-plugin-admin,Vivalldi/grav-plugin-admin,dimayakovlev/grav-plugin-admin,Vivalldi/grav-plugin-admin