BTC & Fiat forecast included

What's Changed

• Three input UI by @MarkKiehlmann in #42
• Update for advanced: miner selection by @MarkKiehlmann in #43
• dbd-fetch: and miner charts aand tables by @MarkKiehlmann in #44
• codex-refactor2/miner-insights - done by @MarkKiehlmann in #45
• ff-btccals: BTC forecast, Fiat forecast and unified forecast (almost) by @MarkKiehlmann in #46
• ff-cumulative: but really a refactor of layout.md by @MarkKiehlmann in #47
• ff-refactor4: test files by @MarkKiehlmann in #48
• ff-refactor5: lots more good stuff by @MarkKiehlmann in #49

Full Changelog: v0.18.0...v0.19.0