News submission feature

In order to support the community better we need a place on the site where the community can submit news.

- Login is required to create a submission.
- Submissions go into a queue for moderation.

There may be different classes of submissions:

- link backs
- content
- events

Content is to be in markdown form and the current "standard" markdown editor is to be available in the form.

The form should capture the 4 Ws (Who, What, Why, Where) and How. The fields don't have to be named such, but should the form should capture all of these points.

Submissions will be made available in table form. We surely need at least a few mutable fields, such as :

- priority
- labels / flags

The fields above are not required for an MVP. Rather, the 4 Ws and How is the bare minimum.

The marketing team will be responsible for publishing the content through various mediums.

It may be we want some submissions to simply be approved and when approved made available automagically, but that is not clear yet. It is assumed to start with that each submission will manually be dealt with (i.e., a blog post is created from the content manually, an event is added manually). Thus, entries in the hopper at the very least need to be marked as processed

Initial idea for schema:

```
:type, :string, null: false
:status, :string, null: false
:who, :text, null: false
:what, :text, null: false
:when, :text, null: false
:why, :text, null: false
:how, :text, null: false
:additional_info, :text
:links, :text
:suggested_mediums, :map
:supporting_documents, :map
:operator_notes, :map
:flags, :map
:priority, :integer
:submitted_by_id, references(:members, on_delete: :nothing)
:updated_by_id, references(:members, on_delete: :nothing)
:processed_by, references(:members, on_delete: :nothing)
:inserted_at, :utc_datetime
:updated_at, :utc_datetime