videometa: add plane_height field

By adding this field buffer producers can now explicitly set the exact height
of each plane, saving consumers to calculate it manually.

GstVideoMeta is always heap allocated by GStreamer itself so we can
safely extend it.
21 jobs for slice-height-618 in 45 minutes and 16 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Preparation
passed #432684
gst indent

00:00:27

passed #432683
manifest

00:00:30

 
  Build
passed #432690
build cerbero android universal

00:22:16

passed #432691
build cerbero cross win32

00:09:25

passed #432692
build cerbero cross win64

00:06:23

passed #432689
build cerbero fedora x86_64

00:13:04

manual #432694
gst-ios-12.2 allowed to fail manual
build cerbero ios universal
passed #432693
gst-macos-10.14
build cerbero macos x86_64

00:06:52

passed #432685
build fedora x86_64

00:17:31

passed #432686
build nodebug fedora x86_64

00:14:58

passed #432687
build static fedora x86_64

00:30:41

passed #432688
build static nodebug fedora x86_64

00:29:25

 
  Test
failed #432695
check fedora

00:06:06

passed #432696
integration testsuites fedora

00:14:03

passed #432700
valgrind bad

00:10:27

passed #432697
valgrind base

00:10:49

passed #432701
valgrind ges

00:08:20

passed #432698
valgrind good

00:07:12

passed #432699
valgrind ugly

00:03:14

 
  Integrate
skipped #432702
android universal examples
skipped #432703
documentation
 
Name Stage Failure
failed
check fedora Test
           Total: 3109
Uploading artifacts...
gst-build/build/meson-logs/: found 2 matching files
validate-logs: found 3527 matching files

Uploading artifacts to coordinator... ok
id=432695 responseStatus=201 Created token=Pc5CZHBY
Uploading artifacts...
validate-logs/*.xml: found 1 matching files

Uploading artifacts to coordinator... ok
id=432695 responseStatus=201 Created token=Pc5CZHBY
ERROR: Job failed: exit code 1