gstreamer1.0: upgrade to version 1.18.0

gstreamer1.0: upgrade to version 1.18.0

    * 0001-gst-gstpluginloader.c-when-env-var-is-set-do-not-fal.patch
      Submited
      https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/669

    * 0002-meson-build-gir-even-when-cross-compiling-if-introsp.patch
      Removed since these are included in 1.18.0

    * 0003-meson-Add-valgrind-feature.patch
      Removed because upstream don't depend anymore on valgrind
      https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/595

    * 0002-Remove-unused-valgrind-detection.patch
      Upstream-Status: Backport [a2cbf75523cdf8a4df1baa7007d86ef455972245]
      https://gitlab.freedesktop.org/gstreamer/gstreamer/-/commit/a2cbf75523cdf8a4df1baa7007d86ef455972245

    API and plugin documentation are no longer built with gtk_doc.
    The gtk_doc documentation has been removed in favour of a new unified
    documentation module built with hotdoc.
    Distributors should use the documentation release tarball instead of trying
    to package hotdoc and building the documentation from scratch.

Signed-off-by: Jose Quaresma <quaresma.jose@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>