Include more hidden files in projectfilter plugin (CI, Lint configs...)

Motivated by 58e6d4c6 this commit adds a few more standard files to
include in the project filter by default:

  -- gitlab, travis, circleCI CI config
  -- pre-commit commit hooks config
  -- pep8 (Python), prettier (JS, CSS, HTML formatter, see Prettier.io)
     linter/formatter configs
  -- .editorconfig file