feat(setting): implement basic local storage data exporter/importer

[ygrishajev]

refs #56

[Redm4x]

Importing data will overwrite any existing data of the same key right? In my implementation of the Import from Cloudmos feature I ended up only importing new keys and merging existing wallets for certs. In this case users will most likely only import data if they have no current data (ex: got wiped), but I'm wondering if we should put a warning that existing data may be overwritten. Wdyt?

[ygrishajev]

That was my concern as well. I'm not sure we need to try guessing what user wants. Having a warning is ideal imo too

[ygrishajev]

@Redm4x @baktun14 to address what we discussed with @Redm4x above added a confirmation popup on data import attempt.
Also added a handy popup context/hook with promised based confirm method. This can be extended to other methods too. This approach reduces boilerplate code/duplication quite a bit.