Remove the `s2n_quic_platform::time` module

[camshaft]

Problem:

The s2n_quic_platform::time module is currently only being used by the default address_token provider.

Solution:

This module should be removed and instead pass the current timestamp as part of the address token context. This will make it easier to integrate the default provider with the IO provider's clock value. This is especially important in environments where the clock is simulated like turmoil and the testing IO provider.