Merge branch '379197-remove-flowdock' into 'master'

Remove Flowdock integration

See merge request !102394



Merged-by: Kati Paizee <kpaizee@gitlab.com>
Approved-by: Piotr Skorupa <pskorupa@gitlab.com>
Approved-by: Ashraf Khamis <akhamis@gitlab.com>
Approved-by: Brian Rhea <brhea@gitlab.com>
Approved-by: Farnoosh Seifoddini <fseifoddini@gitlab.com>
Approved-by: Kati Paizee <kpaizee@gitlab.com>
Co-authored-by: Arturo Herrero <arturo.herrero@gmail.com>
Co-authored-by: Luke Duncalfe <lduncalfe@gitlab.com>
Co-authored-by: Aleksei Lipniagov <alipniagov@gitlab.com>