Dumpable definition of #any? and #all? methods for Channel#mode

Dumpable definition of #any? and #all? methods for Channel#mode

Commit 847a977b228b35f5ab281a31dd3724a4db887dff "#any? and #all? methods
for Channel#mode to check if modes are set" turned Channel into a
non-marshallable object because of singleton methods.

Revert the commit and define an ad-hoc ModeHash class with the any? and
all? methods, to make Channel#mode of that class.