feat: state helper

[richardruiter]

Description

Please include a summary of the change and which issue is fixed.

State helper gets the mocked state value using a key send within the cookie header.
If no value is found it will use the default context within the block.

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Create a mock like this and set a cookie client side

{
"has_pending_order": {{#state key='has-pending-order'}}false{{/state}},
"cart": {{#state key='cart'}}[
{"id": 999, "name": "default prod"}
]{{/state}}
}

Checklist:

• My code follows the guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• This does not break any existing functionalities
• Any dependent changes have been merged and published in downstream modules