MBS-14092: Add support for series of series

[reosarevok]

Implement MBS-14092

Description

This adds a series_series view, and appropriate series types (“Series series” and “Series award”).

We need to have two different column names in the view since we cannot call both series, I went with series_part. Related to that, we need some specialcasing in Data::Series, since we generally expect the structure of series views to be one series column and one $entity_type column but we need to special-case it to series_part for series.

Similarly, some places needed changes to understand that a series having non-series-series parts is acceptable.

We infer the right order for part of series where both sides are series but we know one cannot be the parent (since it does not have a 'series' item_entity_type).

This currently disables the JS level item_entity_type check otherwise since it currently doesn't support checking for direction and having an error blocks the change of direction anyway, making it unfixable. It could be improved to disallow changing the order if only one option would be valid. No wrong relationships can be entered, since the Perl layer still rejects them, but in a less user-friendly way.

Testing

Manually so far, by:

• Adding a series award series.
• Ensuring you can add other series to it
• Ensuring the series can be of any type
• Ensuring the right order is picked by default when only one order makes sense
• Ensuring the part series shows the link back to the containing series:

• Ensuring the display of the series of series makes sense:

[mwiencek]

$type is also used for the table name, so this looks like an error

[reosarevok]

Good point - seems I never caught it because we don't actually use this at the moment anyway for series (nor artists or works). Not sure if we should also call reorder_for_entities on those entities' update methods?

[mwiencek]

Yeah, I'm pretty sure this should run at least when the entity name changes, since that's potentially used for sorting; see e.g. the after update subroutine in Data::ReleaseGroup.

[reosarevok]

Seems sensible. I added all of those in an extra commit (and rebased this).

[mwiencek]

This ID is already used by event-url fanpage. Can we avoid hardcoding this and just do (SELECT id FROM link_type WHERE gid = :SERIES_PART_OF_SERIES_GID) instead?

[mwiencek]

Just make sure to do SELECT setval('link_type_id_seq', (SELECT MAX(id) FROM link_type)); first.

[mwiencek]

I see you also require using the row ID in the source code. Would you be able to add the link type today, in production, with an empty description for now so that it's disabled? (Then set the description in the upgrade script.)