refactor: cart token param name consistent to cartToken

[trojanh]

Resolves #4642
Impact: minor
Type: refactor

Issue

Cart tokens currently have three names i.e token, cartToken and anonymousAccessToken, need to rename all of them to same consistent name.

Solution

Update token or anonymousAccessToken params name to cartToken to make it consistent

Breaking Changes

Clients (such as those based on the example storefront codebase) that call cart-related mutations will need to pass cartToken param instead of token or anonymousAccessToken

Testing

1. Test the following mutations:
   updateCartItemsQuantity
setEmailOnAnonymousCart
removeCartItems
reconcileCarts
addCartItems

2. Test following query
   anonymousCartByCartId

[aldeed]

@trojanh These changes look good but I don't want to merge this until the release-v3.0.0 branch of example-storefront also has a PR submitted updating the mutations and state logic there. (The purpose of this issue was to simplify some things in the example storefront.) If you're not familiar with storefront codebase, @willopez may be able to help or do the storefront PR.

[trojanh]

Thanks, @aldeed I would like do the storefront changes as well. I will definitely take @willopez 's help if needed.

[trojanh]

I have made the changes for front-end,
reactioncommerce/example-storefront#616

[willopez]

I reviewed and merged the related PR on the storefront reactioncommerce/example-storefront#616 this one is good to go too. Thanks again @trojanh