Add bool() filter to Esphome Jinja template engine

[larrybarello]

Describe your core improvement

I use key/value in the command line to configure my top level yaml. It would be convenient to have "esphome -s somekey true/false compile some.yaml" There are a lot of filters implemented but bool seems absent.:

packages:
  f1: ${package_a if (somekey | bool(false)) == true else package_b}

Of course, this can be simulated by using text only, but it could be confusing since the command line always passes text but internally the variable could be "bool" e.g. the following always evaluates to true regardless of the string being passed in.

... -s somekey false ...

 ${ foo if somekey == true else ...}

This should work, but I admit to not having tried it.

packages:
  f1: ${package_a if somekey == "true" else package_b


### Current limitations

Apparently none since I seemed to be the first person to run across this issue and there were reasonable alternatives.

### Technical benefits

Minor improvement.

### Additional context

_No response_