Migrate API keys to the new Secret Storage API

[vibbix]

Background

Currently, the API keys are just stored in the app settings. This isn't recommended anymore,

Changes

• migrated all legacy keys to the new system
• all places where keys got retrieved now use secretStorage

Testing

Validated locally end-to-end

Disclosure

No LLM's were used to write any code as part of this ticket.

[esm7]

Thank you, at first glance it looks great! I'm currently traveling and have very little computer time, but in a couple of weeks I'll invest time on Map View updates, and will give this a proper review & merge :)

[vibbix]

Just checking in, did you have a chance to look over this? I have a follow-up as well to enable additional routing via OpenRailwayMap as well, that depended on this that I wanted to add.

[esm7]

Hi, unfortunately I didn't yet have that time I thought I'll have to invest on Map View updates, including this :(
I was not aware of OpenRailwayMap and it looks amazing, an extremely worthy addition to Map View. It would be best if you create a branch on top of this one, and when the time finally comes, we can integrate both.
Sorry for the trouble, wish I could get to it faster!