Node.gitignore include support for SvelteKit, Vite, Firebase, and .env.example

[taronaeo]

Reasons for making this change:

1. SvelteKit - Upon running npm run build / yarn build, Vite generates a .svelte-kit folder that should not be part of the Git repository.
2. .env.example - Examples of environment files should be part of the Git repository for setup and reference.
3. Vite - Vite may generate temporary log files in the project that may be accidentally committed.
4. Firebase - firebase-tools generates cache directory .firebase to speed up build processes. Not strictly needed in the Git repository.

Links to documentation supporting these rule changes:

1. Firebase - https://stackoverflow.com/a/52131191

[spirit-x64]

Second case (.env.example) should be fixed by #4234