Improve Var and Field Expressions

[Awilum]

Add ability to get, set, unset and delete entries variables and fields.

Usage:

# set
[[ set('foo', 'Foo') ]]

# get
[[ var('foo') ]]
[[ get('foo') ]] 
[[ foo ]]

# unset
[[ unset('foo') ]]

# delete
[[ delete('foo') ]] 

This new functionality will extend current var and field expression functions.

demo: https://twitter.com/_awilum/status/1565730094919958529