Validate method call inside t-foreach loop

Validate if a method that always returns the same result is called inside a t-foreach loop to avoid unnecessary method calls and performance issues.

This is an obvious thing for some experienced programmers but not for the newbies, here is an example of what should't be done

<t t-foreach="attributes" t-as="attribute">
    <t t-set="so" t-value="request.website.sale_get_order()"/>
    #
    # do something with the so variable.
    #
</t>

what to do:

<t t-set="so" t-value="request.website.sale_get_order()"/>
<t t-foreach="attributes" t-as="attribute">
    #
    # do something with the so variable.
    #
</t>

The conditions that the lint should met are:

The method call is inside a t-foreach loop
The method call doesn't receive any argument
The method is not called with a special context and the context has some value as an arg _with_context(somevalue)

OCA / pylint-odoo

Validate method call inside t-foreach loop #299