Add localized Microsoft Store badge / button (Fixes #14738)

[alexgibson]

One-line summary

• Adds a localized badge for linking to Firefox on the Microsoft Store.
• Adds MS Store URL helper and button macro.
• Records MS Store badge click events in GA / Glean.

Issue / Bugzilla link

#14738

Testing

Add the following code to any template to render the badge:

{% from "macros.html" import ms_store_button with context %}

{% set ms_store_href = ms_store_url(product='firefox') %}
{{ ms_store_button(href=ms_store_href) }}

You can also point to Firefox Beta on the Ms Store using:

{% set ms_store_href = ms_store_url(product='firefox_beta') %}
{{ ms_store_button(href=ms_store_href) }}

A campaign ID can be added as an optional parameter:

{% set ms_store_href = ms_store_url(product='firefox', campaign='firefox-all') %}
{{ ms_store_button(href=ms_store_href) }}

Finally, the installer mode can be changed (defaults to direct)

{% set ms_store_href = ms_store_url(product='firefox', mode='full') %}
{{ ms_store_button(href=ms_store_href) }}

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.29%. Comparing base (7babc30) to head (068ab11).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14745      +/-   ##
==========================================
+ Coverage   77.27%   77.29%   +0.02%     
==========================================
  Files         160      160              
  Lines        8273     8281       +8     
==========================================
+ Hits         6393     6401       +8     
  Misses       1880     1880              

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[alexgibson]

Thanks both for these suggestions, will follow up shortly 👍

[alexgibson]

Updated helper with suggestions (thanks @robhudson!) and also optimized SVGs (thanks @janbrasna!)

[craigcook]

LGTM! r+ 🦡

I kinda wish it was the same size and shape as the iOS and Android badges, but presumably their brand guidelines won't let us change it (and it won't appear alongside those badges anyway... unless MS brings back WinCE).

[janbrasna]

@craigcook This is how they present it (not) "side by side":