NetServices: format code using `haiku-format`

This commit formats all the netservices2 code with the `haiku-format` tool from
https://github.com/owenca/haiku-format (commit aa7408e), with the following
customizations:
* SpaceBeforeRangeBasedForLoopColon is set to false
* Braces before a catch block are not wrapped
* Most headers, except for ExclusiveBorrow.h, have been manually reformatted
to adhere to Haiku's header format (issue #19 in the repository)

Change-Id: I693c4515cf26402e48f35d1213ab6d5fcf14bd1e

NetServices: Refactor to make HttpParser stateful

This change refactors various parts of the HTTP parsing. The HttpParser now
tracks what part of the message needs to be received next, and throws an error
if the object is used in the wrong way (when the caller requests to parse the
wrong part of he message).

The metadata about the transmission is now also saved in te parser. There is
partial work in there to start exposing the 'bytes written', which in
compressed streams is expected to differ from the bytes read. This is not
used yet.

This also simplifies the state tracking done by BHttpSession::Request.

Change-Id: I8532c6a5c8776456ea8bbccd6df7a44bac92b60d

NetServices: Add custom error message to BNetworkRequestError

Change-Id: I03970762531a689e25cd78a1091aecf755ee87ce

NetServices: Remove BHttpRequest::SerializeTo(BDataIO*)

The private version that serializes to a HttpBuffer is now used.

Change-Id: I034933a641e98b3a8f918470a024ba32ea7c8663

NetServices: add the HttpSerializer helper to help serialize requests

Change-Id: Ide1e2d387884ce4cf2d406057960cd0732d61f38

NetServices: move HttpBuffer and HttpParser into their own header/source

Change-Id: I5bc0d9df6f94c2cf1c39baa6206bf6f1db284705