text: Title: Support setting values for child suites with `VAR` syntax using `scope=SUITES`
  Body: The current VAR syntax does not support the children argument offered by the `Set Suite Variable` Keyword.
  
  https://robotframework.org/robotframework/latest/libraries/BuiltIn.html#Set%20Suite%20Variable
  
  ```
  Set Suite Variable    ${SUITE_VAR}    I can be used by child suites.    children=True
  ```
  
  
  Syntax like this should be possible:
  
  ```
  VAR    ${SUITE_VAR}    I should be usable by child suites.    scope=SUITE    children=True
  ```
  
  