Add c_bindings version of InvoiceRequestBuilder

Add c_bindings version of InvoiceRequestBuilder

Use the macros introduced in the previous commit to define two builders
for each type parameterization of InvoiceRequestBuilder
- InvoiceRequestWithExplicitPayerIdBuilder
- InvoiceRequestWithDerivedPayerIdBuilder

The difference between these and InvoiceRequestBuilder is that these
have methods that take `self` by mutable reference instead of by value
and don't return anything instead returning the modified builder. This
is required because bindings don't support move semantics nor impl
blocks specific to a certain type parameterization. Because of this, the
builder's contents must be cloned when building an InvoiceRequest.

Keeps InvoiceRequestBuilder defined so that it can be used internally in
ChannelManager::pay_for_offer even when compiled for c_bindings.