Merge branch 'hex-flake-id' into 'develop'

Replace `Pleroma.FlakeId` with `flake_id` hex package

See merge request pleroma/pleroma!1692

diff --cc lib/pleroma/application.ex
Simple merge

diff --cc lib/pleroma/user.ex
Simple merge

diff --cc lib/pleroma/web/activity_pub/activity_pub.ex
Simple merge

diff --cc lib/pleroma/web/common_api/utils.ex
Simple merge

diff --cc mix.exs
Simple merge

diff --cc mix.lock
Simple merge