Remove Send trait bounds from argument bind() calls

[bobozaur]

Is your feature request related to a problem? Please describe.
I wondered about the Send trait bounds required when binding arguments to, say, a Query, because it is the only thing preventing things like an Encode impl for std::fmt::Arguments.

While there's the Text adapter, it relies on a Display impl, so you need a dedicated type with a given Display impl to encode a message. std::fmt::Arguments is more dynamic, but it is not Send.

Describe the solution you'd like
I experimented with removing Send from the various bind() like methods and things seem to still work. The arguments buffer still is and probably needs to be Send, but arguments passed in bind() calls and encoded away don't really seem to need to be thread-safe, as the encoding is a sync operation.

Text could then in fact even rely on the Encode impl of std::fmt::Arguments.

Describe alternatives you've considered
Leave things as they are. It's not a big deal, but just a bit more performance and flexibility in encoding formatted messages without allocations.

Additional context
N/A.