docs: css: Split out any main-page CSS to local.css

Our other sub-projects such as the libvirt-wiki and soon also the
libvirt-security-notices will use the same CSS via asset import script.

Move any specifics into 'local.css' which will be defined by the
sub-projects so that 'main.css' can be imported directly.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

docs/css/local.css

@@ -0,0 +1,3 @@
+@import url(libvirt.css);
+@import url(libvirt-api.css);
+@import url(mobile-libvirt.css);

docs/css/main.css

@@ -1,7 +1,5 @@
 @import url(fonts.css);
 @import url(generic.css);
-@import url(libvirt.css);
-@import url(libvirt-api.css);
 @import url(libvirt-template.css);
 @import url(mobile-template.css);
-@import url(mobile-libvirt.css);
+@import url(local.css);

docs/css/meson.build

@@ -4,6 +4,7 @@ docs_css_files = [
   'libvirt.css',
   'libvirt-api.css',
   'libvirt-template.css',
+  'local.css',
   'main.css',
   'mobile-template.css',
   'mobile-libvirt.css',