resolve_my_address() was beyond repair in terms of refactoring. Way too
complex and doing too many things.

This commit implements find_my_address() which in theory does the same as
resolve_my_address() but in a more clean, concise and modern way using the
tor_addr_t interface and for multiple address family.

The caller needs to pass the address family (IPv4 or IPv6) which this
interface supports. For both, a last resolved cache is used as well.

Implements #33233

Signed-off-by: David Goulet <dgoulet@torproject.org>