Add support for Expo Secure Storage

[km00776]

Add expo-sqlite/kv-store to the persist plugins list.

More about the expo-secure-store

Usage:

import {observablePersistExpoSecureStore} from '../../expo-secure-store/persist-plugins/expo-secure-store'

const persistOptions = configureSynced({
  persist: {
    plugin: observablePersistExpoSecureStore({}),
  },
})
syncObservable(
  StorePasscode$,
  persistOptions({
    persist: {
      name:'secure-something',
    },
  }),
)

[km00776]

@jmeistrich

[km00776]

@cabello @minorgod @jmeistrich

Mind reviewing this?