Allow clone and Modifier.toModify to specify hierarchical parameters

[Dr15Jones]

It should be possible to specify a parameter of a parameter hierarchically in the module clone method or in Modifier.toModify. This would allow

foo = bar.clone( **{"a.b": 10} )

which would be equivalent to

foo = bar.clone()
foo.a.b = 10

[cmsbuild]

A new Issue was created by @Dr15Jones (Chris Jones).

@davidlange6, @smuzaffar, @Degano, @davidlt, @Dr15Jones can you please review it and eventually sign/assign? Thanks.

cms-bot commands are list here #13029

[Dr15Jones]

assign core

[cmsbuild]

New categories assigned: core

@Dr15Jones,@smuzaffar you have been requested to review this Pull request/Issue and eventually sign? Thanks

[Dr15Jones]

Replaced by #13210