expose reqwest client and similar things to users using pub use

[xyangst]

i tried using icann_rdap_client, but to use it, i had to add icann_rdap_common as well. but to do a iana_request i also need the reqwest client..

Im not a rust expert, but i think this is common practice from crates that i have used before 🤔

[anewton1998]

Good suggestion.