[ci] Delete azure-pipelines

End of experiment, we might get back to it later

azure-pipelines.yml

@@ -1,10 +0,0 @@
-pool:
-  vmImage: 'Ubuntu 16.04'
-
-steps:
-- script: |
-    sudo apt install -y gcc binutils libtool autoconf automake make pkg-config gtk-doc-tools ragel libfreetype6-dev libfontconfig1-dev libglib2.0-dev libcairo2-dev libicu-dev libgraphite2-dev python python-pip
-    ./autogen.sh --with-freetype --with-glib --with-cairo --with-icu --with-graphite2 --with-fontconfig
-    make -j32
-    make check
-  displayName: 'make'