Add containerised build tooling

[thumperward]

This commit adds container-based tooling which permits the app to be built without any local configuration. This also permits future work to build and publish releases automatically.

Details:

• Add a Visual Studio Code devcontainer which installs and sets up all required tools automatically. This removes the need to have them installed locally.
• Add a simple Maven configuration which builds and packages the app. This also allows tests to be dropped in.
• Swap from Inno Setup to wix(l), which allows the installer to be built from the command line, even on Linux.
• Update the README with exact build steps, including on the generation of native executables and the installer.
• Add pre-commit tooling to automatically lint any changes on commit.