try to download input files once per gamscompile if missing

Purpose of this PR

try to download input files once per gamscompile if missing to avoid that ./start.R --gamscompile fails with some config files because another run was interrupted on the standby partition while distributing input files.
fix the exclusion of coupled config files. The filenames still have the foldername in front of them, so with ^ it doesn't match anymore.

[x] My code follows the coding etiquette
[x] I performed a self-review of my own code
[x] I explained my changes within the PR, particularly in hard-to-understand areas
[x] I checked that the in-code documentation is up-to-date
[x] I adjusted the reporting in remind2 where it was needed
[x] I adjusted forbiddenColumnNames in readCheckScenarioConfig.R in case the PR leads to deprecated switches
[x] All automated model tests pass (FAIL 0 in the output of make test)
[x] The changelog CHANGELOG.md has been updated correctly