Consider using capacitor to build native Android and iOS mapper apps

[spwoodcock]

Is your feature request related to a problem? Please describe.

• Capacitor allows for pretty much the same code to be used for web, native android, native ios.
• The advantage of the native (app store) builds is that they can use native APIs (e.g. we won't have geolocation restrictions from web browsers).

Describe the solution you'd like

• Add capacitor.
• Add android and iOS targets.
• Update geolocation code to use capacitor.
• Compile native builds.
• Distribute via app stores.

Additional context

• We can do this for the mapper frontend only.
• Its an extra maintainence burden. App store listings must be made and maintained. Also need to regularly update to keep mobile SDK version recent (else the app eventually gets removed from the store).
• This should be assessed further to see if its worth the burden (mainly for improved geolocation and orientation via accelerometer API).