pulsesrc: Move to extended stream API

This is needed as a precursor to allowing capture of IEC61937
formats. We now also need to include the channel map while converting
format info to caps so that a correct channel mask is generated for
pulsesrc's caps.
8 jobs for master in 62 minutes and 47 seconds (queued for 10 seconds)
Status Job ID Name Coverage
  Preparation
passed #77374
gst indent

00:00:17

passed #77373
manifest

00:00:25

 
  Build
passed #77375
build fedora x86_64

00:02:10

 
  Test
passed #77376
check fedora

00:18:05

 
  Full Builds
passed #77377
build android arm64 api28

00:04:20

passed #77379
build cerbero cross win32

00:17:07

passed #77380
build cerbero cross win64

00:14:41

passed #77378
build cerbero fedora x86_64

00:14:49