Add lacking decision log docu to spec

[krvoigt]

Current situation We decided to place the information in different sections in spec.

• decision log, Web API, Workflow
• decision log contains an overview of decistions (what and why) and links to more detailed documentation in spec
• we already have a draft for that in spec @lena-hinrichsen
• we collected lacking docu that needs to be provided that way

User Story As a developer and technical user, I would like to have an overview of the current architecture and documentation of key architectural decisions so that I have a better understanding of the architecture and how I can implement OCR-D.

Steps

Missing docu:

• [x] we decided to use Nextflow as a workflow engine, and the whole .nf file (Nextflow file) as the workflow format workflow server and processing server including web API implementation is part of the impl projects (Mehmet, Triet)
• [x] OCR-D Koord provides the Web API spec. Only the REST API wrapper of a single processor is provided by OCR-D Core. (Jonas, Triet)
• [x] [Changes/Upgrades to our tech stack] (https://pad.gwdg.de/zVTkp0B0TOy8FCxkPVHvTg#) (Konstantin) : supported python versions linux base image ** additional libraries/software (MongoDB, uvicorn...) (
• [x] Switch to Slim Containers in ocrd_all (Konstantin)
• [x] Python API changes (Konstantin)

Acceptance Criteria

• [x] currently lacking information is provided
• [x] the docu is accessible for all people who might be interested in (public?)

Prior Art

• WIP Pad: https://pad.gwdg.de/KRhbnDIbQUikojfPmpaM-g?both
• https://github.com/ocr-d/zenhub/issues/105

[lena-hinrichsen]

@kba Can this (and the related issues) be closed or should the Decision Log be more detailed about anything here?

[kba]

No, I think this is all covered. Now the hard part is implementing those changes...