Move HDY_STYLE_PROVIDER_PRIORITY_OVERRIDE to hdy-main.c

This allows removing hdy-style-private.h, as there is no point in
keeping it if it's only included by hdy-main.c and only contains a
macro definition.
11 jobs for static-style-init in 17 minutes and 47 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #248454
librem5
api-visibility

00:02:50

passed #248456
librem5
build-debian-clang

00:04:01

passed #248455
librem5
build-debian-gcc

00:03:11

passed #248457
librem5
build-fedora-gcc

00:03:18

 
  Test+Docs
passed #248458
librem5
build-gtkdoc

00:02:25

passed #248459
librem5
unit-test

00:02:22

43.2%
 
  Package
passed #248460
librem5
package-debian-buster

00:02:45

passed #248461
librem5:arm64
package-debian-buster:arm64

00:06:29

failed #248462
flatpak allowed to fail
package-flatpak

00:00:09

 
  Test Package
passed #248463
librem5
autopkgtest-debian-buster-package

00:02:35

passed #248464
librem5
lintian-debian-buster-package

00:00:55

 
Name Stage Failure
failed
package-flatpak Package There has been a runner system failure, please try again
Running with gitlab-runner 12.6.0 (ac8e767a)
on arm01-runner 53gNDtDb
ERROR: Preparation failed: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? (executor_docker.go:982:0s)
Will be retried in 3s ...
ERROR: Preparation failed: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? (executor_docker.go:982:0s)
Will be retried in 3s ...
ERROR: Preparation failed: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? (executor_docker.go:982:0s)
Will be retried in 3s ...
ERROR: Job failed (system failure): Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? (executor_docker.go:982:0s)