v0.9.4: backend overhaul + Symbol rebranding

Added

• FormAccountUnlock: standardize practice of unlocking account across app
• FormTransactionBase: base abstraction layer for transaction forms
• SignerSelector: generic transaction signer selector, works with multisig to change owned assets states
• General change of views files (*.vue) paths with result :
  • Components in src/components/
  • Modal Dialogs in src/views/modals/
  • Pages in src/views/pages/
  • Layouts in src/components/
  • Forms in src/views/forms/
• Added namespaced vuex Store managing application state changes
• Added namespaces vuex Store managing REST requests changing state (action REST_*)
• Added src/core/database/ with LocalStorageBackend, models and tables schemas
• Added repository abstraction layer to work with persistent storage
• Added business layer implementations in src/services/*
• Rewrote all route names and use route names instead of paths for redirects

Known Issues

• Missing harvesting setup (account link & persistent delegation requests)
• Some missing UI fixes for Symbol rebrand
• Mosaic definition multi-signature feature bug with signer selection (aggregate bonded only)