Standardise project & streamline build

[Pathoschild]

This pull request makes some changes to streamline building the code on any computer, update the manifest, and simplify the mod folder name.

• Project structure:
  • Standardised the project structure & simplified metadata.
  • Added a .gitignore to automatically exclude files that shouldn't be checked in.
  • Added a .gitattributes to normalise line endings between Linux/Mac/Windows.
  • Renamed the solution (SDV_ShopTest → StardewMods) and project (M007_ExtendedFridge → ExtendedFridge).
• Mod build:
  • Added the missing manifest.json and updated it for the latest SMAPI.
  • Migrated to the mod build package.
    This automates references (so we no longer need to change reference paths in the .csproj), lets us compile the mod on Linux/Mac/Windows without changes, simplifies debugging from Visual Studio, and lets us deploy the mod into the game's Mods folder automatically.
  • Bumped the version for release.
• Code:
  • Reduced code accessibility where possible.
  • Show the current mod version in the UI automatically (previously hardcoded to 0.96).