chore: Add README and licenses to streaming assets

Assets/StreamingAssets/Messages/LICENSE.txt

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+# License
+The following files are licensed under [CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/) © Cryville and translation contributors.
+
+- Cryville.EEW.Core/*
+- Cryville.EEW.CWA/*
+- Cryville.EEW.CWAOpenData/*
+- Cryville.EEW.CWAOpenData.TTS/*
+- Cryville.EEW.FERegion/yue.json
+- Cryville.EEW.FERegion/zh.json
+- Cryville.EEW.FERegion/zh-Hant.json
+- Cryville.EEW.GlobalQuake/*
+- Cryville.EEW.JMA/*
+- Cryville.EEW.JMA/PointTsunami/en.json
+- Cryville.EEW.JMA/PointTsunami/yue.json
+- Cryville.EEW.JMA/PointTsunami/zh.json
+- Cryville.EEW.JMA/PointTsunami/zh-Hant.json
+- Cryville.EEW.JMAAtom/*
+- Cryville.EEW.JMAAtom.TTS/*
+- Cryville.EEW.NOAA/*
+- Cryville.EEW.NOAA.TTS/*
+- Cryville.EEW.UpdateChecker/*
+- Cryville.EEW.Wolfx/*
+- Cryville.EEW.Wolfx.TTS/**/*
+
+The following files are copyrighted by [Japan Meteorological Agency](https://www.jma.go.jp/jma/index.html):
+
+- Cryville.EEW.FERegion/ja.json (modified)
+- Cryville.EEW.JMA/AreaEpicenter/* (modified)
+- Cryville.EEW.JMA/AreaForecastEEW/* (modified)
+- Cryville.EEW.JMA/AreaTsunami/* (modified)
+- Cryville.EEW.JMA/PointTsunami/und.json
+- Cryville.EEW.JMA/PointVolcano/* (modified)
+
+The following files are from [Wikipedia](https://en.wikipedia.org/wiki/Flinn-Engdahl_regionalization#/map/0), licensed under [CC-BY-SA-4.0](https://creativecommons.org/licenses/by-sa/4.0/deed.en):
+
+- Cryville.EEW.FERegion/und.json (modified)

Assets/StreamingAssets/Messages/LICENSE.txt.meta

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