Support filtering works by multiple work_statuses and by updated_at_with_relations

[rhigman]

Required for automatic dissemination (initially to Crossref), where we need to find works which are either ACTIVE or FORTHCOMING, and which have had their metadata updated within a certain timeframe (i.e. since the last scheduled dissemination - as we will be making both initial submissions and updates).

Also enables filtering by multiple language_relations. Filtering by updated_at_with_relations requires specifying a timestamp and whether the field value should be greater than (after) or less than (before) this timestamp.

[ja573]

Overall, rather than TimeExpression I'm more inclined to support filtering by field more widely. Something like:

pub enum Operator {
    Eq,
    Neq,
    Gt,
    Lt,
    Gte,
    Lte,
    Ilike,
}

pub struct WorkFilter {
    pub field: WorkField,
    pub operator: Operator,
    pub value: String,
}

fn works (
        [...]
        filters: Vec<WorkFilter>,
        [...]
)

[ja573]

Instead of replacing the current argument, keep both for the time being to avoid breaking dependants. The current GraphQL specification doesn't allow marking arguments as deprecated (though it will in the next release), so we'll just need to rely on using the description as the deprecation notice

[rhigman]

As discussed, due to other priorities, we'll keep the basic TimeExpression filtering for now and improve it later under #486.

[ja573]

We should also keep language_relation and flag it as deprecated like work_status

[ja573]

I'm just thinking that it'd also be good to update thoth-client/assets/schema.json, even though it's not exactly needed