fix: Align path variable for export and import routes to use Shortcode

[seakayone]

Pull Request Checklist

Task Description/Number

Issue Number: DEV-2399

Align import and export endpoint to use Shortcode as identifier in both routes.

Remove unused factory method Shortcode.make(Option[String]).

Basic Requirements

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• fix: represents bug fixes
• refactor: represents production code refactoring
• feat: represents a new feature
• docs: documentation changes (no production code change)
• chore: maintenance tasks (no production code change)
• test: all about tests: adding, refactoring tests (no production code change)
• other... Please describe:

Does this PR introduce a breaking change?

• Yes
• No
• Maybe (not 100% sure => check with FE)

Does this PR change client-test-data?

• Yes (don't forget to update the JS-LIB team about the change)
• No

[codecov]

Codecov Report

Patch coverage: 31.08% and project coverage change: -8.46 ⚠️

Comparison is base (12402f3) 18.00% compared to head (ad4eb7f) 9.54%.

Additional details and impacted files

@@            Coverage Diff            @@
##             main   #2734      +/-   ##
=========================================
- Coverage   18.00%   9.54%   -8.46%     
=========================================
  Files         281     281              
  Lines       28899   28895       -4     
=========================================
- Hits         5202    2759    -2443     
- Misses      23697   26136    +2439     

Impacted Files	Coverage Δ
...sponder/projectsmessages/ProjectsPayloadsADM.scala	0.00% <0.00%> (ø)
...ora/webapi/responders/v1/ProjectsResponderV1.scala	0.00% <0.00%> (-4.52%)	⬇️
...rg/knora/webapi/routing/admin/ProjectsRouteZ.scala	94.11% <0.00%> (+2.68%)	⬆️
.../org/knora/webapi/routing/v1/ProjectsRouteV1.scala	0.00% <0.00%> (ø)
...org/knora/webapi/routing/v1/ResourcesRouteV1.scala	0.00% <0.00%> (ø)
...ice/admin/api/service/ProjectsADMRestService.scala	48.57% <0.00%> (-11.43%)	⬇️
...i/slice/admin/domain/service/DspIngestClient.scala	0.00% <0.00%> (-4.77%)	⬇️
.../slice/admin/domain/service/KnoraProjectRepo.scala	0.00% <0.00%> (ø)
...ce/admin/domain/service/ProjectExportService.scala	0.00% <0.00%> (-68.19%)	⬇️
...n/domain/service/ProjectExportStorageService.scala	17.39% <0.00%> (-5.34%)	⬇️
... and 7 more

... and 92 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[BalduinLandolt]

LGTM