Add grid extension to disable filters submit button when filters are empty

[zuk3975]

Questions	Answers
Branch?	develop
Description?	Configured grid template to initialize filters search button as "disabled" if filters are empty. Added javascript grid extension to enable the button when inputs are being filled by user.
Type?	improvement
Category?	BO
BC breaks?	no
Deprecations?	no
Fixed ticket?	#12439
How to test?	In all migrated lists, when page is loaded with empty list filters, the filter search button should be disabled and the reset button should be hidden. Once the user starts typing (or selecting) filters, search button should be enabled and reset button is shown. On page load if there is already some filters, the search and reset buttons are also shown and enabled.

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This change is 

[zuk3975]

@matks, ready for judgement. There are still couple things:

1. The styling slightly differs from products list - when both buttons are shown, in products list search button is lined up with filters, in other lists, buttons are vertically aligned in middle. Not sure which one is better option, but i guess its the second (as it came with new grid).
2. Search is enabled once something is typed in inputs/selects, but its not disabled after everything is deleted (except when resetting). I am refering to products page, but this behavior doesn't seem right to me.

[mickaelandrieu]

Hello @zuk3975,

as it is for the next minor we may migrate the products list page at the same time, so don't worry about the difference of behavior between products and the other pages using the Grid component.

Ping @sarjon: is it possible to document and describe every js extension and how to create a new one?
This is something missing in the current docs :(

Mickaël

[sarjon]

is it possible to document and describe every js extension and how to create a new one?

Hey @mickaelandrieu, it is possible. Abracadabra and here we have a good start! PrestaShop/docs#240 🎉 😃