Support coloring for "don't care" files

[nqminhuit]

For example I have these:

system master .editorconfig .gitmodules launch.json pom.xml
console master
domain master
grpc master
log master
scheduler master

The root module is system which contains some files I want to mark as "don't care" and should have a faint color scheme e.g., light grey
This setting can put in the gis.config file