videoconvert: Preserve and forward upstream colorimetry

When upstream provides colorimetry explicitly, preserve it as mush as
possible and set the converted colorimetry to output caps.

Closes gstreamer/gst-plugins-base#614
32 jobs for forward-colorimetry in 50 minutes and 43 seconds (queued for 7 seconds)
latest
Status Job ID Name Coverage
  Preparation
passed #1658140
gst indent

00:00:53

passed #1658139
manifest

00:00:32

 
  Build
passed #1658150
gstreamer
build cerbero cross-android universal

00:07:40

passed #1658154
gst-ios-13.2
build cerbero cross-ios universal

00:20:10

passed #1658151
gstreamer
build cerbero cross win32

00:09:28

passed #1658152
gstreamer
build cerbero cross win64

00:05:40

passed #1658149
gstreamer
build cerbero fedora x86_64

00:04:05

passed #1658153
gst-macos-10.15
build cerbero macos x86_64

00:10:57

passed #1658145
build clang fedora x86_64

00:07:10

passed #1658141
build fedora x86_64

00:04:40

passed #1658148
docker windows 1809
build msys2

00:39:52

passed #1658142
build nodebug fedora x86_64

00:03:20

passed #1658155
build rust fedora x86_64

00:19:08

passed #1658143
build static fedora x86_64

00:12:38

passed #1658144
build static nodebug fedora x86_64

00:02:47

passed #1658146
docker windows 1809
build vs2017 amd64

00:11:12

passed #1658147
docker windows 1809
build vs2017 x86

00:10:43

 
  Test
passed #1658156
gstreamer
check fedora

00:03:53

passed #1658166
gstreamer
check rust fedora

00:06:19

passed #1658157
gstreamer
integration testsuites fedora 1/4

00:16:30

passed #1658158
gstreamer
integration testsuites fedora 2/4

00:13:49

passed #1658159
gstreamer
integration testsuites fedora 3/4

00:20:09

passed #1658160
gstreamer
integration testsuites fedora 4/4

00:14:09

passed #1658164
gstreamer
valgrind bad

00:07:06

passed #1658161
gstreamer
valgrind base

00:08:48

passed #1658165
gstreamer
valgrind ges

00:08:03

passed #1659505
gstreamer
valgrind good

00:08:29

passed #1658163
gstreamer
valgrind ugly

00:02:16

failed #1658162
gstreamer
valgrind good

00:11:59

 
  Integrate
passed #1658167
cross-android universal examples

00:09:11

passed #1658169
gst-ios-13.2
cross-ios universal examples

00:02:54

passed #1658168
documentation

00:02:59