[GNC-dev] build stats/badges for GNC maint, 3.6, 3.5 using Docker

[Dale Phurrough]

Hi all. I finished the second stage of my project to automate build/test of
GnuCash with Docker. See the badges, drill down to logs and individual test
results at
https://diablodale.github.io/gnucash-dev-docker/

In previous emails you read about the easy consistent GnuCash build/test
with Docker.
https://github.com/diablodale/gnucash-dev-docker

   - Updated with clearer categorized build dependencies in Dockerfiles
   - Used these Docker containers to build/test across 14 distrib/versions
   of Linux
   - Containers can be built locally or downloaded from DockerHub
   - Automated build and tests using these containers via CI on AppVeyor
   - Transformed ctest results through XSLT to JUnit format
   - Exposed build and test results to badges

Still to do

   - Microsoft Azure CI Pipelines offers a free tier of CI that could be
   used and 10x faster. I will explore their offering to see if it meets needs
   - Windows builds. Thanks to JohnR and GeertJ, good progress has been
   made. I have the responsibility for next steps. I need to return to my
   testing to see what is missing or not functioning.
   - Watch and evaluate AppVeyor. I exposed several bugs in the AppVeyor
   offering as well as some limitations that required workarounds. I've
   reported the issues to the AppVeyor team.
   - Evaluate a switch to this docker build/test for GitHub PR testing. The
   existing Travis process being used has aged and doesn't test a full suite
   of functionality. With experience using AppVeyor and/or Microsoft CI, the
   core GnuCash team can evaluate switching away from the old Travis method.
   - Any related requests? Please send them to me.

--Dale