Add type guards in query functions

[Maks-s]

As the user can type whatever they want as arguments, this PR changes the query functions' parameters' types to unknown and adds type guards to provide better exception handling.

Here's an example, using the following snippet

```template
{{replace(45, "4", "5")}}

**Without type guards**
![uh](https://github.com/silverbulletmd/silverbullet/assets/26678512/9b657c7e-6d7a-47d4-a02a-a336c93dc4cb)

**With type guards**
![nice](https://github.com/silverbulletmd/silverbullet/assets/26678512/f928b6b3-150a-44b6-aeeb-e95734a3e5b9)

[zefhemel]

Very nice, thank you!