Moving custom ecto types in context folders

See merge request pleroma/pleroma!2652

Remove `poll` from `notification_type` OpenAPI spec

Closes #1867

See merge request pleroma/pleroma!2657

User: Add raw_bio, storing unformatted bio

See merge request pleroma/pleroma!2326

Update elixir image used for OTP releases

See merge request pleroma/pleroma!2654

This is necessary since we bumped required version of elixir to 1.9.

The dlsym bug should be gone by now.

Chunk the notification type backfill migration

See merge request pleroma/pleroma!2653

Long-term we want that migration to be done entirely in SQL,
but for now this is a hotfix to not cause OOMs on large databases.

This is using a homegrown version of `Repo.stream`, it's worse in
terms of performance than the upstream since it doesn't use the same
prepared query for chunk queries, but unlike the upstream it supports
preloads.

Resolve "/api/v1/conversations returns the wrong `last_status`"

Closes #1866

See merge request pleroma/pleroma!2647

Upgrade to Elixir 1.9

See merge request pleroma/pleroma!2651

Mogrify args in adminFE

Closes #1787

See merge request pleroma/pleroma!2616

warning: :hackney_connect.partial_chain/1 is undefined or private

Merge OGP parser with TwitterCard

Closes #1835

See merge request pleroma/pleroma!2642