General service component for OGC API Processes

[MartinPontius]

OGC standard document: https://docs.ogc.org/is/18-062r2/18-062r2.html

• Implement logic to fetch and parse job result (currently only the job status is fetched) [GET request to, e.g., https://api.saferplaces.co/jobs/b6a5237a-616c-11f0-85d8-0a58a9feac02/results?f=json]
• Refactor to trails service https://github.com/open-pioneer/trails-starter/blob/main/docs/tutorials/HowToCreateAService.md
• General clean up (better name package, remove redundant lines/comments, ..)
• In the OPT app add the process output as temporary layer to the TOC (later stage, first get job result in clean working version)