Merge branch 'hotfix/docu'
Merge branch 'hotfix-2.1.28'
Merge branch 'master' of https://github.com/MISP/MISP
Merge branch 'hotfix-2.1.28'
Loosened the filename validation on attachments

- filenames without extensions were blocked for example
Merge branch 'hotfix-2.1.29' into develop