Remove media-session from this tree

It is now available as a separate project in
https://gitlab.freedesktop.org/pipewire/media-session

This also removes the pw-reserve tool that relied on one source file of
media-session, that tool is now built as part of media session.
34 jobs for wip/drop-media-session in 4 minutes and 38 seconds (queued for 11 seconds)
Status Name Job ID Coverage
  Container
passed container_fedora #14761164

00:00:22

passed container_ubuntu #14761163

00:00:16

 
  Build
passed build_on_fedora #14761166

00:02:31

passed build_on_ubuntu #14761165

00:02:09

passed build_release: [clang] #14761192

00:00:49

passed build_release: [gcc] #14761191

00:00:52

passed build_with_custom_options: [audiotestsrc, disabled] #14761178

00:02:02

passed build_with_custom_options: [audiotestsrc, enabled] #14761177

00:02:22

passed build_with_custom_options: [bluez5-backend-hsphfpd, disabled] #14761176

00:02:02

passed build_with_custom_options: [bluez5-backend-hsphfpd, enabled] #14761175

00:02:20

passed build_with_custom_options: [docs, disabled] #14761170

00:01:58

passed build_with_custom_options: [docs, enabled] #14761169

00:02:22

passed build_with_custom_options: [installed_tests, disabled] #14761172

00:01:58

passed build_with_custom_options: [installed_tests, enabled] #14761171

00:02:21

passed build_with_custom_options: [sdl2, disabled] #14761188

00:02:17

passed build_with_custom_options: [sdl2, enabled] #14761187

00:02:19

passed build_with_custom_options: [sndfile, disabled] #14761190

00:00:49

passed build_with_custom_options: [sndfile, enabled] #14761189

00:00:52

passed build_with_custom_options: [systemd-system-service, disabled] #14761174

00:02:02

passed build_with_custom_options: [systemd-system-service, enabled] #14761173

00:02:24

passed build_with_custom_options: [test, disabled] #14761180

00:02:22

passed build_with_custom_options: [test, enabled] #14761179

00:02:23

passed build_with_custom_options: [videotestsrc, disabled] #14761182

00:02:19

passed build_with_custom_options: [videotestsrc, enabled] #14761181

00:02:21

passed build_with_custom_options: [volume, disabled] #14761184

00:02:19

passed build_with_custom_options: [volume, enabled] #14761183

00:02:17

passed build_with_custom_options: [vulkan, disabled] #14761186

00:02:19

passed build_with_custom_options: [vulkan, enabled] #14761185

00:02:19

passed build_with_no_commandline_options: [clang] #14761168

00:02:04

passed build_with_no_commandline_options: [gcc] #14761167

00:01:54

passed valgrind #14761193

00:00:33

 
  Analysis
passed doccheck #14761196

00:01:42

passed shellcheck #14761194

00:00:55

passed spellcheck #14761195

00:00:53