Get metadata of already created ERC in OJS via the o2r API

[tomniers]

get extracted Metadata an fill out OJS wit these values:
https://o2r.info/api/#operation/get_metadata
GET /api/v1/compendium/:id/metadata
https://o2r.uni-muenster.de/api/v1/compendium/geQfc/metadata
Metadata that can be extracted: https://raw.githubusercontent.com/o2r-project/o2r-meta/master/schema/json/o2r-meta-schema.json

• Add besides title and abstract further elements which are integrated automatically in OJS
• Let the user decide in the plugin settings if the user wants to have the automatic metadata fill in activated or not

[tomniers]

5f740d7
Enabled example implementation of requesting metadata from the o2r server. Via pushing a button in the submission process, the user can request metadata for a given ERC (defined by the ERC Id entered by the user in the frontend). This requested metadata is then automatically filled in into the given fields in OJS. This was here exemplary implemented for the title.

Later on the user should be able to decide in the settings and not by a button, if the metadata extracted by the o2r server should be automatically filled in for a newly in OJS created ERC.

[tomniers]

6fa26d7
The metadata requested for a certain compendium which was uploaded during the OJS submission process to the o2r service are automatically integrated into the elements in step 3. of the submission process in OJS. At the moment it is done exemplary for the title and the abstract, further elements can follow. Additionally it should be decidable for the user in the plugin settings if the user wants to have this automatic metadata fill in activated or not.