Traducir guías de Mejores Prácticas


#### Root del folder `best-practices/`:
- `a11y.md`
- `error-handling.md` 
- `style-guide.md`
- `update.md` 

#### Subfolder `best-practices/runtime-performance/`:
- `overview.md`
- `profiling-with-chrome-devtools.md`
- `skipping-subtrees.md`
- `slow-computations.md`
- `zone-pollution.md`