Get projects vocabularies from Annif API instead of project ids

[juhoinkinen]

Currently the vocabulary that a project uses is determined from the project id (prefix):

FintoAI/ai.finto.fi/static/js/annif.js

Lines 339 to 340 in aa05c02

	// Assume vocabulary id is a prefix of project id
	this.vocab_ids = [...new Set(this.projects.map(item => item.project_id.split("-")[0]))];

Now, since NatLibFi/Annif#839, it is possible to get that information from Annif API, and when Annif version with the updated API is deployed to Finto AI, the js-code should be updated to utilize this.