docker/windows: refactorings to get it to work with the new runner

* Install git-lfs as its required now by gst-integration-suites
* Clone gst-build eache time to avoid dated gst-build checkouts
and overwritting .wrap files. Similar to !137
* Split the dockerfile and add a second run stage refresh the
powershell env inbetween calls
* Remove the msys2 workaround as its not needed anymore
26 jobs for master in 32 minutes and 8 seconds (queued for 10 seconds)
Status Job ID Name Coverage
  Build Docker
manual #511208
allowed to fail manual
alpine amd64 manifest builder docker
manual #511218
allowed to fail manual
android docker
manual #511216
allowed to fail manual
cerbero fedora amd64 docker
manual #511214
allowed to fail manual
fedora amd64 docker
manual #511212
allowed to fail manual
gst-indent amd64 docker
manual #511210
allowed to fail manual
test manifest amd64 docker
 
  Preparation
passed #511220
gst indent

00:00:21

passed #511219
manifest

00:00:30

passed #511221
test manifest

00:00:22

 
  Build
passed #511230
build cerbero android universal

00:13:25

passed #511231
build cerbero cross win32

00:08:01

passed #511232
build cerbero cross win64

00:08:58

passed #511229
build cerbero fedora x86_64

00:05:27

manual #511234
gst-ios-12.2 allowed to fail manual
build cerbero ios universal
passed #511233
gst-macos-10.14
build cerbero macos x86_64

00:09:18

passed #511222
build fedora x86_64

00:09:42

passed #511228
docker windows 1607
build msys2

00:12:18

passed #511223
build nodebug fedora x86_64

00:06:04

passed #511224
build static fedora x86_64

00:12:21

passed #511225
build static nodebug fedora x86_64

00:11:56

passed #511226
docker windows 1607
build vs2017 amd64

00:10:18

passed #511227
docker windows 1607
build vs2017 x86

00:09:51

 
  Test
passed #511235
check fedora

00:05:00

passed #511236
integration testsuites fedora

00:12:18

 
  Integrate
passed #511237
android universal examples

00:05:52

passed #511238
documentation

00:04:00