Remove WWW entries moved into port Makefiles

Commit b7f05445c00f has added WWW entries to port Makefiles based on
WWW: lines in pkg-descr files.

This commit removes the WWW: lines of moved-over URLs from these
pkg-descr files.

Approved by:		portmgr (tcberner)

Add WWW entries to port Makefiles

It has been common practice to have one or more URLs at the end of the
ports' pkg-descr files, one per line and prefixed with "WWW:". These
URLs should point at a project website or other relevant resources.

Access to these URLs required processing of the pkg-descr files, and
they have often become stale over time. If more than one such URL was
present in a pkg-descr file, only the first one was tarnsfered into
the port INDEX, but for many ports only the last line did contain the
port specific URL to further information.

There have been several proposals to make a project URL available as
a macro in the ports' Makefiles, over time.

framework: convert bsd.gstreamer.mk to Uses/gstreamer.mk

- convert bsd.gstreamer.mk to Uses/gstreamer.mk
- convert ports tree to make use of USES=gstreamer
- remove duplicate dependency lines from the tree

Differential Revision: https://reviews.freebsd.org/D35097

One more small cleanup, forgotten yesterday.
Reported by:	lwhsu

Remove # $FreeBSD$ from Makefiles.

multimedia/svt-vp9: update to 0.3.0

Changes:	https://github.com/OpenVisualCloud/SVT-VP9/releases/tag/v0.3.0
Reported by:	GitHub (watch releases)

multimedia/svt-vp9: update to 0.2.2

Changes:	https://github.com/OpenVisualCloud/SVT-VP9/releases/tag/v0.2.2
Reported by:	GitHub (watch releases)
MFH:		2020Q3 (unbreaks SVTVP9 in multimedia/ffmpeg)

multimedia/svt-vp9: update to 0.2.1

Changes:	https://github.com/OpenVisualCloud/SVT-VP9/releases/tag/v0.2.1
Reported by:	GitHub (watch releases)

multimedia/svt-vp9: update to 0.2.0 (retag)

Changes:	https://github.com/OpenVisualCloud/SVT-VP9/compare/fee9c46..v0.2.0
Reported by:	GitHub (watch releases)

multimedia/svt-vp9: update to 0.2.0 (retag)

Changes:	https://github.com/OpenVisualCloud/SVT-VP9/compare/381690c..v0.2.0
Reported by:	GitHub (watch releases)

multimedia/svt-vp9: update to 0.2.0

Changes:	https://github.com/OpenVisualCloud/SVT-VP9/releases/tag/v0.2.0
Reported by:	GitHub (watch releases)

multimedia: Add missing USES={gl,gnome,sdl,xorg}

multimedia/svt-vp9: update to 0.1.0 (retag)

Changes:	https://github.com/OpenVisualCloud/SVT-VP9/compare/3535884...v0.1.0
Reported by:	GitHub (watch releases)

multimedia/svt-vp9: back out r514290 per forced push upstream

https://github.com/OpenVisualCloud/SVT-VP9/issues/62

=======================<phase: fetch          >============================
===>  License BSD2CLAUSE+PATENT accepted by the user
=> OpenVisualCloud-SVT-VP9-v0.1.1_GH0.tar.gz doesn't seem to exist in
/portdistfiles/.
=> Attempting to fetch
https://codeload.github.com/OpenVisualCloud/SVT-VP9/tar.gz/v0.1.1?dummy=/OpenVisualCloud-SVT-VP9-v0.1.1_GH0.tar.gz
fetch:
https://codeload.github.com/OpenVisualCloud/SVT-VP9/tar.gz/v0.1.1?dummy=/OpenVisualCloud-SVT-VP9-v0.1.1_GH0.tar.gz:
Not Found
=> Attempting to fetch
http://distcache.FreeBSD.org/ports-distfiles/OpenVisualCloud-SVT-VP9-v0.1.1_GH0.tar.gz
fetch:
http://distcache.FreeBSD.org/ports-distfiles/OpenVisualCloud-SVT-VP9-v0.1.1_GH0.tar.gz:
Not Found
=> Couldn't fetch it - please try to retrieve this
=> port manually into /portdistfiles/ and try again.
*** Error code 1

Reported by:	pkg-fallout

multimedia/svt-vp9: update to 0.1.1

Changes:	https://github.com/OpenVisualCloud/SVT-VP9/compare/v0.1.0...v0.1.1
Reported by:	GitHub (watch releases)

multimedia/svt-vp9: update to 0.1.0 (nop)

Changes:	https://github.com/OpenVisualCloud/SVT-VP9/compare/39bb49a...v0.1.0

multimedia/svt-vp9: update to s20190927

Changes:	https://github.com/OpenVisualCloud/SVT-VP9/compare/68b81bd...39bb49a

multimedia/*svt-{av1,vp9}: correct year of the snapshot

multimedia/svt-*: hook GStreamer plugins