qtdemux: implement support for trickmode interval

When the seek event contains a (newly-added) trickmode interval,
and TRICKMODE_KEY_UNITS was requested, only let through keyframes
separated with the required interval
20 jobs for qtdemux-trickmode-interval in 119 minutes and 2 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Preparation
passed #431169
gst indent

00:00:46

passed #431168
manifest

00:00:29

 
  Build
passed #431175
build cerbero android universal

00:10:36

passed #431176
build cerbero cross win32

00:11:43

passed #431177
build cerbero cross win64

00:07:42

passed #431174
build cerbero fedora x86_64

00:07:49

manual #431179
gst-ios-12.2 allowed to fail manual
build cerbero ios universal
passed #431178
gst-macos-10.14
build cerbero macos x86_64

00:08:06

passed #431170
build fedora x86_64

00:11:26

passed #431171
build nodebug fedora x86_64

00:06:30

passed #431172
build static fedora x86_64

00:13:40

passed #431173
build static nodebug fedora x86_64

00:10:55

 
  Test
passed #431645
check fedora

00:03:41

passed #431181
integration testsuites fedora

00:28:43

passed #431183
valgrind bad

00:06:52

passed #431184
valgrind ges

00:12:09

passed #431182
valgrind good

00:26:08

failed #431180
check fedora

00:04:39

 
  Integrate
passed #431185
android universal examples

00:06:43

passed #431186
documentation

00:05:14