Feature request: support (and forward) the `verbose` keyword argument in HTTP.jl

[Dilum Aluthge]

Possibly, an improvement in FHIRClient could be to support the verbosity keyword argument in HTTP.jl and forward it to HTTP.request for adjusting the verbosity of the logging messages from HTTP: https://juliaweb.github.io/HTTP.jl/stable/reference/#HTTP.request

Originally posted by @devmotion in #130 (comment)