[security] transport.Controller{} and transport.Transport{} security and performance improvements (#564)

* cache transports in controller by privkey-generated pubkey, add retry logic to transport requests

Signed-off-by: kim <grufwub@gmail.com>

* update code comments, defer mutex unlocks

Signed-off-by: kim <grufwub@gmail.com>

* add count to 'performing request' log message

Signed-off-by: kim <grufwub@gmail.com>

* reduce repeated conversions of same url.URL object

Signed-off-by: kim <grufwub@gmail.com>

* move worker.Worker to concurrency subpackage, add WorkQueue type, limit transport http client use by WorkQueue

Signed-off-by: kim <grufwub@gmail.com>

* fix security advisories regarding max outgoing conns, max rsp body size

- implemented by a new httpclient.Client{} that wraps an underlying
  client with a queue to limit connections, and limit reader wrapping
  a response body with a configured maximum size
- update pub.HttpClient args passed around to be this new httpclient.Client{}

Signed-off-by: kim <grufwub@gmail.com>

* add httpclient tests, move ip validation to separate package + change mechanism

Signed-off-by: kim <grufwub@gmail.com>

* fix merge conflicts

Signed-off-by: kim <grufwub@gmail.com>

* use singular mutex in transport rather than separate signer mus

Signed-off-by: kim <grufwub@gmail.com>

* improved useragent string

Signed-off-by: kim <grufwub@gmail.com>

* add note regarding missing test

Signed-off-by: kim <grufwub@gmail.com>

* remove useragent field from transport (instead store in controller)

Signed-off-by: kim <grufwub@gmail.com>

* shutup linter

Signed-off-by: kim <grufwub@gmail.com>

* reset other signing headers on each loop iteration

Signed-off-by: kim <grufwub@gmail.com>

* respect request ctx during retry-backoff sleep period

Signed-off-by: kim <grufwub@gmail.com>

* use external pkg with docs explaining performance "hack"

Signed-off-by: kim <grufwub@gmail.com>

* use http package constants instead of string method literals

Signed-off-by: kim <grufwub@gmail.com>

* add license file headers

Signed-off-by: kim <grufwub@gmail.com>

* update code comment to match new func names

Signed-off-by: kim <grufwub@gmail.com>

* updates to user-agent string

Signed-off-by: kim <grufwub@gmail.com>

* update signed testrig models to fit with new transport logic (instead uses separate signer now)

Signed-off-by: kim <grufwub@gmail.com>

* fuck you linter

Signed-off-by: kim <grufwub@gmail.com>

go.sum

@@ -40,9 +40,12 @@ codeberg.org/gruf/go-bitutil v1.0.0/go.mod h1:sb8IjlDnjVTz8zPK/8lmHesKxY0Yb3iqHW
 codeberg.org/gruf/go-bytes v1.0.0/go.mod h1:1v/ibfaosfXSZtRdW2rWaVrDXMc9E3bsi/M9Ekx39cg=
 codeberg.org/gruf/go-bytes v1.0.2 h1:malqE42Ni+h1nnYWBUAJaDDtEzF4aeN4uPN8DfMNNvo=
 codeberg.org/gruf/go-bytes v1.0.2/go.mod h1:1v/ibfaosfXSZtRdW2rWaVrDXMc9E3bsi/M9Ekx39cg=
-codeberg.org/gruf/go-byteutil v1.0.0 h1:xgKFNj/gH1r3yRo7gnyR4qrAKyeWCXs6B19ISX0DUAY=
 codeberg.org/gruf/go-byteutil v1.0.0/go.mod h1:cWM3tgMCroSzqoBXUXMhvxTxYJp+TbCr6ioISRY5vSU=
+codeberg.org/gruf/go-byteutil v1.0.1 h1:cOSaqe2aytOTAC5NM62LI0w8qPfJ9n2BBddk5KyMgd0=
+codeberg.org/gruf/go-byteutil v1.0.1/go.mod h1:cWM3tgMCroSzqoBXUXMhvxTxYJp+TbCr6ioISRY5vSU=
 codeberg.org/gruf/go-cache v1.1.2/go.mod h1:/Dbc+xU72Op3hMn6x2PXF3NE9uIDFeS+sXPF00hN/7o=
+codeberg.org/gruf/go-cache/v2 v2.0.1 h1:dyyfn6W6jfUlD/HWu5oz48sowSgsfKKeg2lU6T0gRww=
+codeberg.org/gruf/go-cache/v2 v2.0.1/go.mod h1:VyfrDnPVUXUKYVkXnFOHRO1EoN+8zrTC9jRU6VmL3p0=
 codeberg.org/gruf/go-debug v1.1.2 h1:7Tqkktg60M/4WtXTTNUFH2T/6irBw4tI4viv7IRLZDE=
 codeberg.org/gruf/go-debug v1.1.2/go.mod h1:N+vSy9uJBQgpQcJUqjctvqFz7tBHJf+S/PIjLILzpLg=
 codeberg.org/gruf/go-errors/v2 v2.0.0/go.mod h1:ZRhbdhvgoUA3Yw6e56kd9Ox984RrvbEFC2pOXyHDJP4=