* add delivery worker type that pulls from queue to httpclient package
* finish up some code commenting, bodge a vendored activity library change, integrate the deliverypool changes into transportcontroller
* hook up queue deletion logic
* support deleting queued http requests by target ID
* don't index APRequest by hostname in the queue
* use gorun
* use the original context's values when wrapping msg type as delivery{}
* actually log in the AP delivery worker ...
* add uncommitted changes
* use errors.AsV2()
* use errorsv2.AsV2()
* finish adding some code comments, add bad host handling to delivery workers
* slightly tweak deliveryworkerpool API, use advanced sender multiplier
* remove PopCtx() method, let others instead rely on Wait()
* shuffle things around to move delivery stuff into transport/ subpkg
* remove dead code
* formatting
* validate request before queueing for delivery
* finish adding code comments, fix up backoff code
* finish adding more code comments
* clamp minimum no. senders to 1
* add start/stop logging to delivery worker, some slight changes
* remove double logging
* use worker ptrs
* expose the embedded log fields in httpclient.Request{}
* ensure request context values are preserved when updating ctx
* add delivery worker tests
* fix linter issues
* ensure delivery worker gets inited in testrig
* fix tests to delivering messages to check worker delivery queue
* update error type to use ptr instead of value receiver
* fix test calling Workers{}.Start() instead of testrig.StartWorkers()
* update docs for advanced-sender-multiplier
* update to the latest activity library version
* add comment about not using httptest.Server{}
* update activity library so dereferencer returns full response and checks *final* link to allow for redirects
* temporarily add bodged fixed library
* remove unused code
* update getAccountFeatured() to use dereferenceCollectionPage()
* make sure to release map
* perform a 2nd decode to ensure reader is empty after primary decode
* add comment explaining choice of using Decode() instead of Unmarshal()
* update embedded activity library to latest matching https://github.com/superseriousbusiness/activity/pull/21
* add checks to look for changed URI and re-check database if redirected
* update max iteration count to 512, add checks during dereferenceAncestors() for indirect URLs
* remove doubled-up code
* fix use of status instead of current
* use URIs for checking equality for security
* use the latest known URI for boost_of_uri in case original was an indirect
* add dereferenceCollection() function for dereferenceAccountFeatured()
* pull in latest github.com/superseriousbusiness/activity version (and remove the bodge!!)
* fix typo in code comments
* update decodeType() to accept a readcloser and handle body closing
* switch to checking using BoostOfID and add note why not using BoostOfURI
* ensure InReplyTo gets unset when deleting status parent in case currently stubbed
* add tests for Collection and CollectionPage iterators
