Academy: Add entry point/registration/listings for participating organizations in need of documentation

[tillkamppeter]

The Open Documentation Academy is all about helping free software organizations to find technical authors to contribute to their documentation.

Currently, we have only the list of issues of this repository as documentation tasks on offer. Many potential contributors would like to browse by organization. They also would like to see a summary of what each participating organization does and what their documentation workflows and policies are.

Therefore I suggest a self-registration for organizations searching for documentation contributors.

By registration, the organization's profile should be easily accessible on the program's web site, similar to the mentoring organizations for the Google Summer of Code.

I suggest the following fields:

• Name: (one-line string) The organization's name
• Description: (multi-line, markdown supported) What does the organization do in free software?
• Documentation methodology/workflow/policy: (multi-line, markdown supported) How does the organization handle documentations? Which tools? Data formats? Workflows? Policies? Automation techniques? Diataxis? Links to documentation, documentation, given talks, videos, ... about writing the organization's documentation ...
• Code license: (one-line string + SPDX license selection)
• Documentation license: (one-line string + SPDX license selection)
• Web site scripting license: (one-line string + SPDX license selection) Documentation writing sometimes involves scripting on the organization's web site
• Tags: (array of one-line strings) Tags for potential contributors easily find the desired organizations
• Organization's bug/issue tracker, ideally GitHub: (link) Where to find and report documentation issues
• Organization label: (on-line string) Issues on the Academy GitHub (this repo) should have this label to mark the issue belonging to this organization
• Organization's documentation label: (array of one-line strings) Which label(s) uses the organiztion to mark documentation issues in their repo?

In addition, metrics could be displayed with each organization, like number of available documentation issues, how many are successfully solved, ..., and also links to show the list of organization's documentation issues.

Searching should be available by name of organization, tags, full-text of description and methodology, licenses.

@degville WDYT?