Fix for issue 10423

[u7492883]

Added a fetcher for the webside ISIDORE, (https://isidore.science/). The fetcher will get all the fields that it can find and will convert them into a BibEntry.
Fixes #10423.

Mandatory checks

• Change in CHANGELOG.md described in a way that is understandable for the average user (if applicable)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.

[Siedlerchr]

It looked already good on a first quick look, no idea why you closed this. I would maybe sugget to use the json output insteaed of the xml and addtionally I would implement it as SearchBasedParserFetcher

[u7492883]

Sorry I named it incorrectly so I opened a new pull request that was more descriptive. I did not use the json output as I believe there is a bug where it does not work, as an example the following link https://api.isidore.science/resource/content?output=json&uri=10670/1.d2vlam, should output a json file but it only gives the xml file. Please let me know if I have made a mistake here.

[koppor]

For reference, the new PR is #10518