Prevent possible XSS issues by seting text/plain for all text files in
RAW feature

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fixes #7571
Merge branch 'stable-xss-fix' into '7-2-stable'

Stable xss fix

See merge request !1048
Update the CHANGELOG for 7.2.1
Bump VERSION to 7.2.1