[#1167] Steps 3 & 4 - download chain tip metadata from lightwalletd

[LukasKorba]

Closes #1167
Closes #1169

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Author

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• Run the app: Did you run the app and try the changes? While the CI server runs the app to look for build failures or crashes, humans running the app are more likely to notice unexpected log messages, UI inconsistencies, or bad output data.