Migrate adapter admin configuration to jsonConfig and short-form i18n files

[Copilot]

This PR migrates the adapter admin UI from legacy Materialize HTML to jsonConfig while preserving existing native config structure and field semantics. It also converts admin translations to the short-form admin/i18n/<lang>.json layout and removes obsolete admin UI assets.

• Admin UI migration (materialize → jsonConfig)

  • Added admin/jsonConfig.json as the new configuration source.
  • Switched io-package.json to:

    "adminUI": { "config": "json" }

  • Modeled native.devices as a table with unchanged attributes:
    • name, mac, ip, pin, pollInterval, enabled
  • Included full responsive sizing (xs, sm, md, lg, xl) on the table config.

• Config compatibility and data handling

  • Kept configuration keys and types stable to avoid backend/runtime changes.
  • Preserved PIN handling in UI config via encrypted table attribute:

    "encryptedAttributes": ["pin"]

• i18n format migration

  • Replaced nested translation files (admin/i18n/<lang>/translations.json) with short-form files:
    • admin/i18n/de.json, en.json, es.json, fr.json, it.json, nl.json, pl.json, pt.json, ru.json, uk.json, zh-cn.json
  • Populated translations from existing admin/words.js.

• Legacy admin asset cleanup

  • Removed obsolete files no longer used after jsonConfig migration:
    • admin/index_m.html
    • admin/style.css
    • admin/words.js