Cleanup old JS files

[Hlavtox]

Questions	Answers
Branch?	develop
Description?	Removes old unused JS methods. Most of these are related to 1.6 product page and other migrated pages. I did not remove any methods that are actively used, possibly in 3rd party modules utilizing legacy components. Files that were not used at all were removed completely.
Type?	refacto
Category?	BO
BC breaks?	yes
Deprecations?	no
How to test?
UI Tests
Fixed issue or discussion?
Related PRs
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[Hlavtox]

@kpodemski Ready

[kpodemski]

Let's not rush this PR, I see that you removed some commonly used functions like updateLinkRewrite or toggleLanguageFlags, basically all the functions that probably are still in use when people use HelperForm and old controllers.

There are some that are more safe to delete like:

stockManagementActivationAuthorization
orderOverwriteMessage
toggleShippingCost
orderDeleteProduct
changeCMSActivationAuthorization

I remember some modules where I've seen fancyChooseBox function, meaning those "helper functions" are relevant and should stay there, while those who are related to migrated pages, could probably be deleted.

etc.

It is too dangerous to remove all of these methods at once.