Add set methods

[zunda-arrow]

This PR also optimizing how cloning works so components created with a decorator are never mutated. Im not sure how to best document this.

closes #47

[zunda-arrow]

This may be too jank. This code would not work as expected.
It does follow a simple rule "functions will never be mutated" but idk. I don't think cloning is expensive enough to have this issue. Its so much cheaper than component.set() currently that you won't be slowing down functions that much.

@flare.button()
def button():
   ...

a = button.set_label("1234")
b = a.set_label("a")
c = a.set_label("b")

print(button.label)  # None
print(a.label)  # b
print(b.label)  # b
print(c.label)  # b

[zunda-arrow]

Another solution is requiring a method to be called before any changes to a button. Like .clone() or something. This would make it very explicit when a clone is made but it bloats up the API so I would rather clone everything and optimize later with rust/a custom clone function or something.

[zunda-arrow]

Now whenever you mutate anything it clones. Cloning is at least 5x faster than the serializing method so its quite cheap really.

[hypergonial]

Cloning go brrrrr