Add source code link, license and language/platform tag to all entries

[nodiscc]

Contribution guidelines have been updated (https://github.com/awesome-foss/awesome-sysadmin/blob/master/.github/PULL_REQUEST_TEMPLATE.md) and now include:

• Format your submission as follows, where Demo and Clients are optional. Do not add a duplicate Source code link if it is the same as the main link. Keep the short description under 80 characters and use sentence case for it, even if the project's webpage or readme uses another capitalisation. Demo links should only be used for interactive demos, i.e. not video demonstrations.
  - [Name](http://homepage/) - Short description, under 250 characters, sentence case. ([Demo](http://url.to/demo), [Source Code](http://url.of/source/code), [Clients](https://url.to/list/of/related/clients-or-apps)) `License` `Language`
• The Language tag is the main server-side requirement for the software. Don't include frameworks or specific dialects.

All software added before this guideline, should now be updated to mention the source code URL, the Free/Open-source license they use, as well as the main server-side requirement.

There is no main license list, but SPDX identifiers (e.g. GPL-3.0, MIT, Apache-2.0 ...) should be used when possible.

If the software is installed though a language/platform-specific package manager (npm, pip, gem, composer, docker pull...), the language tag should probably be the corresponding language/platform (Nodejs, Python, Ruby, PHP, Docker ...). Programs that can be deployed as a single binary executable can use their respective language tag (C, Go, Rust...).

This will help moving the list towards a machine-readable format awesome-selfhosted/awesome-selfhosted#1038

You can refer to the results of the latest Github actions workflow for a list of entries that do not respect the correct syntax.

[nodiscc]

Fixed in latest master.