feat(mu): Top Up Http Message from AO

[twilson63]

The MU configuration will have a map of address -> nodes, that can be matched when pushing outbox messages.

When a credit-notice is part of the outbox that matches a set of hyperBEAM processes, then the MU should POST a http signed message to the HyperBEAM node endpoint `/~simple-pay@1.0/topup'

[twilson63]

get_balance_and_top_up_test() ->
    {Address, Wallet, Opts} = test_opts(),
    Node = hb_http_server:start_test_node(Opts),
    {ok, Res} =
        hb_http:get(
            Node,
            hb_message:attest(
                #{<<"path">> => <<"/~simple-pay@1.0/balance">>},
                Wallet
            ),
            #{}
        ),
    ?assertEqual(70, hb_converge:get(<<"body">>, Res, #{})),
    {ok, NewBalance} =
        hb_http:post(
            Node,
            hb_message:attest(
                #{
                    <<"path">> => <<"/~simple-pay@1.0/topup">>,
                    <<"amount">> => 100,
                    <<"recipient">> => Address
                },
                Wallet
            ),
            #{}
        ),
    ?assertEqual(140, hb_converge:get(<<"body">>, NewBalance, #{})),
    {ok, Res2} =
        hb_http:get(
            Node,
            hb_message:attest(
                #{<<"path">> => <<"/~simple-pay@1.0/balance">>},
                Wallet
            ),
            #{}
        ),
    ?assertEqual(110, hb_converge:get(<<"body">>, Res2, #{})).