remove sections of ToS relevant to age

[ewdurbin]

As directed by @eximious.

@copiesofcopies two questions:

1. Does anything else need to be changed in support of this?
2. Does this warrant a notification to existing users of a ToS update?

[copiesofcopies]

1. No, I don't believe this impacts any other sections of the Terms of Service or Privacy Policy.
2. Since this change does not impact the rights or obligations of any existing user (since the prospective users this impacts are currently not permitted to use PyPI), I don't believe email notification is required.