Absolish builders for CircMgrConfig and DirMgrConfig
These two structs don't correspond to config sections in the TorClientConfig
. Rather, they are the subsets of the config that these two crates want to use.
Having them use the builder pattern means that when the config variables change, it is possible to mess up the plumbing. And the builder pattern buys us only API stability here in tor-*
, not arti-*
. IMO we should expose this to avoid writing any more bugs of this kind - ie, making it a build error to not initialise needed config fields at these lower layers.