Create API endpoints for bulk deleting

[Senyoret1]

Feature description
It would be good to have API endpoints for removing several transports or routes with just one call.

Is your feature request related to a problem? Please describe.
When there are several elements to remove, the manager UI has to make one call per element, which is very inefficient.

Describe the solution you'd like
API endpoints accepting an array of IDs, instead of just one. If the current endpoints are changed to work with single elements and arrays, that would also work.