Don't use Appveyor

appveyor.yml

@@ -1,64 +0,0 @@
----
-version: 2.11.0.dev.{build}
-
-os: Visual Studio 2019
-platform: x64
-
-environment:
-  BITS: 64
-  CMAKE_BUILD_TYPE: Debug
-  CMAKE_GENERATOR: "Visual Studio 16 2019"
-  CMAKE_GENERATOR_PLATFORM: x64
-  # https://www.appveyor.com/docs/windows-images-software/#boost
-  BOOST_ROOT: 'C:\Libraries\boost_1_71_0'
-  BOOST_LIBRARYDIR: 'C:\Libraries\boost_1_71_0\lib64-msvc-14.2'
-  # https://www.appveyor.com/docs/windows-images-software/#tools
-  OPENSSL_ROOT_DIR: 'C:\OpenSSL-v111-Win64'
-  BISON_BINARY: 'C:\ProgramData\chocolatey\lib\winflexbison3\tools\win_bison.exe'
-  FLEX_BINARY: 'C:\ProgramData\chocolatey\lib\winflexbison3\tools\win_flex.exe'
-
-branches:
-  only:
-    - master
-
-cache:
-- build -> appveyor.yml
-- C:\ProgramData\chocolatey\lib\winflexbison3
-
-install:
-- ps: |
-    if (-not (Test-Path "C:\ProgramData\chocolatey\lib\winflexbison3")) {
-      & choco install winflexbison3
-      if ($LastExitCode -ne 0) { $host.SetShouldExit($LastExitCode) }
-    }
-
-# why that env handling, see
-# https://help.appveyor.com/discussions/questions/18777-how-to-use-vcvars64bat-from-powershell#comment_44999171
-before_build:
-- ps: |
-    & .\tools\win32\load-vsenv.ps1
-
-    & powershell.exe .\tools\win32\configure.ps1
-    if ($LastExitCode -ne 0) { $host.SetShouldExit($LastExitCode) }
-
-    del build\Icinga*.msi
-
-build_script:
-- ps: |
-    & powershell.exe .\tools\win32\build.ps1
-    if ($LastExitCode -ne 0) { $host.SetShouldExit($LastExitCode) }
-
-test_script:
-- ps: |
-    & powershell.exe .\tools\win32\test.ps1
-    if ($LastExitCode -ne 0) { $host.SetShouldExit($LastExitCode) }
-
-# Disable until we really need them
-# https://github.com/Icinga/icinga2/issues/6106
-# https://help.appveyor.com/discussions/problems/10253-maximum-allowed-artifact-storage-size-of-1000-mb-will-be-exceeded
-#artifacts:
-#- path: build/Icinga*.msi
-#- path: build/choco/*.nupkg
-#- path: build/Test.xml
-
-deploy: off