GenerateClass should generate `__init__` with constructor arguments

[lieryan]

Is your feature request related to a problem? Please describe.

Given that FooBar is an undefined class, and you have a code that looks like this:

result = FooBar(
    arg='abc'
)

Currently, Rope will generate a new class structure that looks like this:

class FooBar(object):
    pass


result = FooBar(
    arg='abc'
)

Describe the solution you'd like

Rope should generate the __init__ template and set arguments to self:

class FooBar(object):
    def __init__(self, arg='abc'):
        self.arg = arg


result = FooBar(
    arg='abc'
)

Additional Context

• This feature is currently implemented in rope/contrib/generate.py::GenerateClass
• Some code from GenerateFunction may be reusable here