feat: add elevation support to export

[a-y-a-n-das]

🛠️ Fixes Issue

feat: Add option to include elevation for download

Closes #211

👨‍💻 Changes proposed

• added a prop in buildDirectionRequest to include elevations.
• updated useDirectionQuery to accept a prop for the same and return directions with elevations.
• added a checkbox for elevation in the dropdown.
• With checked, it makes an additional call with params: elevation_interval: 30 before downloading.

📄 Note to reviewers

AI: used for generating tests.

📷 Screenshots

[github-actions]

Preview is ready! 🚀 You can view it here: https://valhalla-app-tests.gis-ops.com/405

[nilsnolde]

A bunch of things are not good tbh:

• the UI is not up to my standards, looks & feels really odd

• this PR breaks the routing logic: if the page is freshly reloaded and we add 2 waypoints in the map it won't auto-request the route, which it needs to do obviously
• doing another /route request is way too heavy! I know this feature will hardly be ever used by people, so in practice it doesn't matter much. it's just a good principle to not waste any byte & CPU cycle. use /height instead, that's pretty much for free.

[a-y-a-n-das]

Yes, sirrr

• A checkbox without any border looks odd.
• I tried reloading the preview, and it's fetching the routes.
• I actually thought of using something other than /route (like the height graph data).

I will try to use that and touch up the UI.

[a-y-a-n-das]

Now using /height
Implemented using fetch due to this #413

[a-y-a-n-das]

Please let me know if any further changes are needed.