HttpRequest: put cookies in a single header entry

 * Http spec says headers can be split when they are comma separated
 * However, cookies are semicolon separated, so it is not acceptable to
split them.
 * We will want to implement some way to limit the cookie header entry
size, as servers have a limit on what they can accept (usually around 4K
characters). The RFC also says we don't need to remember more than 20
cookies per domain.
Remove deprecated package manager mockup app.

 * HaikuDepot was started from scratch and deprecates this.
fix build.