Align REST API with TopQuadrant Maui Server API?

[osma]

I wonder why I didn't discover this earlier, but TopQuadrant has created a Maui Server wrapper for Maui (license: GPL) which provides a comprehensive REST API not only for document analysis (suggest method) but also for creating and training Maui models.

Annif could support the same or very similar REST API for creating and training projects, including defining the vocabulary etc. There is some impedance mismatch (e.g. in Maui a vocabulary belongs under a "tagger" i.e. a project, while in Annif vocabularies can be reused across projects) but in any case the Maui Server API provides a nice example.

[osma]

As a first step, the analyze method was renamed suggest in #268 / PR #272 .