Add actor occupations access points, refs #11081

[jraddaoui]

Introduces a new way to capture, search/browse and import/export information
about actors. Adds a new taxonomy for "Actor occupations" and a custom,
repeatable set of fields with an autocomplete linked to the new taxonomy
and a notes field per access point will be added to actor view and edit pages.

• Add migration and fixtures for new taxonomy and note type
• Create access points section in ISAAR plugin with a multirow table and
  and an autocomplete and text area to enter the occupations and notes
• Add new section and data display to ISAAR index page
• Add new data to actor in the ES index (tweak serialize i18n method to
  allow serializing fields from different objects to the same partial foreing type)
• Add new facet for actor occupations to actor browse page
• Add occupations and notes to EAC XML and actor CSV exports/imports

Refs: #11066, #11067, #11068, #11077, #11078, #11079

[sbreker]

This looks great! Good job breaking up the work into meaningful commits! :)
👍

[jraddaoui]

Thanks Steve, I didn't realize this is a 2.5 feature, so we'll have to wait until qa/2.5.x is created to merge.

[jraddaoui]

In the end it will be included in the 2.4 release. Merged in 67f0e48