feat: enable multiple api specs for each product

[evegufy]

Description

• add script to move multiple OpenAPI specs files in one directory into individual directories
• change to directory path for listing of directories in index.html to enable directory listings also in those individual directories

Why

#20
relates to eclipse-tractusx/portal-backend#1030

Pre-review checks

Please ensure to do as many of the following checks as possible, before asking for committer review:

• DEPENDENCIES are up-to-date. Dash license tool. Committers can open IP issues for restricted libs.
• Copyright and license header are present on all affected files
• Change was successfully tested --> for products that don't provide multiple api specs, the behaviour of the api hub remains unchanged