Fixes and improvements to the CI pipelines.

• Custom fixes to coala: support python3.8 and recent versions of cppcheck
• Adapt .coafile to current coala
• Adapt LicenseYearBear to current svn python package
• Move the linter configuration to the coala directory
• Remove the now unused lint-patch script
• Update Jenkins pipelines to report build stderr as a comment on Unix (including warnings when the build succeeds), and to report lint issues inline

Tested on Jenkins during the past week.

Differential Revision: https://code.wildfiregames.com/D2931