Improve generated type conversions for components

[jleibs]

It would be nice for components to generate a converter From their datatypes such as

impl<T: Into<::re_types_core::ArrowString>> From<T> for Name {
    fn from(v: T) -> Self {
        Self(v.into())
    }
}

However, doing so creates a conflict since the the already generated converter from the Component back to the datatype:

impl From<Name> for ::re_types_core::ArrowString {
    #[inline]
    fn from(value: Name) -> Self {
        value.0
    }
}

meets the bound and in turn creates a conflict with the core-provided impl<T> std::convert::From<T> for T;