Merge branch '1104-change-contact-methods' into 'development'

Resolve "Change contact methods"

Closes #1104 (closed)

See merge request !1820 (merged)

(cherry picked from commit ec190fde)

f53d2777 removed direct mail option 34ed8a16 switched mail adress 695af99e Added possibility to attach files to message 5623cdd6 file upload and validation working properly f3d30689 removed E-Mail Adresses from team website 9a9b216a replaced every mention of email adress with a link to contact form 69476f8a fixed dockerfile 8b2e8dbc attachments are now optional ffcb7163 increased ingress body size