Set Typescript tsconfig.base.ts to strict

Apply the strict settings for the whole workspace:

```json
"strict": true,
    "noFallthroughCasesInSwitch": true,
    "noImplicitReturns": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
```

- https://www.typescriptlang.org/tsconfig#strict
- https://indepth.dev/posts/1402/bulletproof-angular