Merge remote-tracking branch 'stefanha/net' into staging

Merge remote-tracking branch 'stefanha/net' into staging

* stefanha/net:
  remove unused QemuOpts parameter from net init functions
  convert net_init_bridge() to NetClientOptions
  convert net_init_tap() to NetClientOptions
  convert net_init_vde() to NetClientOptions
  convert net_init_socket() to NetClientOptions
  convert net_init_slirp() to NetClientOptions
  convert net_init_dump() to NetClientOptions
  convert net_init_nic() to NetClientOptions
  convert net_client_init() to OptsVisitor
  hw, net: "net_client_type" -> "NetClientOptionsKind" (qapi-generated)
  qapi schema: add Netdev types
  qapi schema: remove trailing whitespace
  qapi: introduce OptsVisitor
  expose QemuOpt and QemuOpts struct definitions to interested parties
  qapi: introduce "size" type
  qapi: generate C types for fixed-width integers
  qapi: add test case for deallocating traversal of incomplete structure
  qapi: fix error propagation
  MAINTAINERS: Replace net maintainer Mark McLoughlin with Stefan Hajnoczi