Redesign donation form

[humphd]

After the email outreach work @emmaelaine did last week, I've been talking with her about how to include some of what she found to be successful in the donation form. Having a more personal, direct message explanation of the goals seems to help a lot. Below is what I've done based on that, and how it looks, first on Desktop, then Mobile.

This change does the following:

• Adds Donation Tiers, that match what we're seeing donors give. The UI makes it easier to get from "I want to help" to actually making a contribution (i.e., you only have to click one button). If you click one of the buttons, it fills-out that number for you, and shows how much money it is. If you type a different number, the buttons aren't highlighted anymore (i.e., you can enter anything you want, too). It's easy to change the tiers to use different values if we want to later.
• The Donate Form now includes some language to help people who land here (e.g., after following social media) to know what the charity is about, how their money is used, and how to give.
• I've included a link to the Summary stats page for more info about the numbers
• I've included some example thank-you messages we've received, which help tell the story about how important this is
• I've moved the "Other Ways to Donate" to the bottom as links vs. scripts/embeds. The way this was being done was causing a bunch of errors in the page, and a lot of it wouldn't load with ad-blockers. All of these links accomplish the same thing.

NOTE: this builds on the stuff I've started to do for the back-end to add integration testing. That work is on-going, and we should NOT update the back-end yet. However, I don't want to block this front-end change, since I think it will help us improve donations.

[mekkim]

This is SUPER AWESOME! I LOVE IT!

[humphd]

This is also ready to go. The failure is due to whatever caused the previous one to also fail (some random blip with the secret being injected). I'm going to merge this one too, and see what it does on main.

[humphd]

As predicted, passes on main: https://github.com/EBSECan/donatemask/runs/6573222302?check_suite_focus=true

I'm going to do a follow-up where the Stripe test, which needs secrets, only runs on main vs. in PRs.

[humphd]

@mekkim this, and the other recent changes are ready to be deployed.

You'll need to run npm install for both the front-end and back-end to get the modules they use, but everything else should be OK.

Let me know if you have any issues.