Create "npm run setup" script

[fmaclen]

• Run every step outlined in the README through a single command
• Update .github/workflow's so they take advantage of such command
• Update README

Reference

1. Install Electron dependencies

% npm install

2. Install SvelteKit dependencies

% cd sveltekit && npm install

3. Generate Prisma's artifacts.

% cd sveltekit && npx prisma generate

4. Create and seed a vault which will be seeded with the minimum required data (account/asset types, categories, etc).

% cd sveltekit && npx prisma migrate dev