Add expression support for type based assertions

[BernieWhite]

Currently the following assertion methods doesn't have an equivalent expression in YAML/ JSON.

• IsArray
• IsBoolean
• IsDateTime
• IsInteger
• IsNumeric

We should add support for these.

[ArmaanMcleod]

@BernieWhite Similar to assertions, should we give the ability to set convert to convert values?

Wondering how this would work with expressions:

---
# Synopsis: Test isBoolean
apiVersion: github.com/microsoft/PSRule/v1
kind: Selector
metadata:
  name: YamlIsBooleanTrue
spec:
  if:
    field: 'Value'
    isBoolean: true
    # How would we enable conversion?

or do we just not convert by default, and "true" would always be false. Or vice versa and convert everything.

[BernieWhite]

@ArmaanMcleod Let's keep the behaviour like assertions. Specifically don't convert by default, but provide a parameter to opt-in to conversion for the assertions that have that currently exposed.

For the assertions that do not have that option, don't convert.

Some limited expressions expose additional properties such as setOf ref. I think we should expose an additional convert bool property that can be true/ false to convert the type.

---
# Synopsis: Test isBoolean
apiVersion: github.com/microsoft/PSRule/v1
kind: Selector
metadata:
  name: YamlIsBooleanTrue
spec:
  if:
    field: 'Value'
    isBoolean: true
    convert: true

[ArmaanMcleod]

@BernieWhite Great, was thinking that would be the easiest way as well.