TR-4557: Update Fastly HTTPS setup guide

[gilesv]

Ticket: https://messagebird.atlassian.net/browse/TR-4557

What Changed

• Updated Fastly guide on HTTPS Engagement Tracking, with screenshots of the new UI and more details about correctly forwarding the Host header to SparkPost.
• Screen recording of the guide:

Screen.Recording.2023-06-27.at.17.59.03.mov

• Link to guide in dev: http://localhost:3000/docs/tech-resources/enabling-https-engagement-tracking-on-sparkpost#step-by-step-guide-with-fastly

After setting up my tracking domain with HTTPS provided by Fastly, I noticed that it automatically forwards the Host if the Override host option is disabled:

~❯ curl -v https://click.redlabs.shop/f/woohoo/XhBKq2IoQzooHYGhQFI21w\~\~/AAUBzwA\~/RgRmfbURP0RJaHR0cHM6Ly9kb2NzLm5naW54LmNvbS9uZ2lueC9hZG1pbi1ndWlkZS9sb2FkLWJhbGFuY2VyL2h0dHAtbG9hZC1iYWxhbmNlclcDc3BjQgpkkREwm2TECMaQUiN2aW5pY2l1cy5naWxlcyt0ZXN0QG1lc3NhZ2ViaXJkLmNvbVgEAAAAAA\~\~
*   Trying 199.232.113.91:443...
* Connected to click.redlabs.shop (199.232.113.91) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*  CAfile: /etc/ssl/cert.pem
*  CApath: none
* (304) (OUT), TLS handshake, Client hello (1):
* (304) (IN), TLS handshake, Server hello (2):
* (304) (IN), TLS handshake, Unknown (8):
* (304) (IN), TLS handshake, Certificate (11):
* (304) (IN), TLS handshake, CERT verify (15):
* (304) (IN), TLS handshake, Finished (20):
* (304) (OUT), TLS handshake, Finished (20):
* SSL connection using TLSv1.3 / AEAD-CHACHA20-POLY1305-SHA256
* ALPN, server accepted to use h2
* Server certificate:
*  subject: CN=click.redlabs.shop
*  start date: Jun 27 17:28:20 2023 GMT
*  expire date: Sep 25 17:28:19 2023 GMT
*  subjectAltName: host "click.redlabs.shop" matched cert's "click.redlabs.shop"
*  issuer: C=US; O=Let's Encrypt; CN=R3
*  SSL certificate verify ok.
* Using HTTP2, server supports multiplexing
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x12780f200)
> GET /f/woohoo/XhBKq2IoQzooHYGhQFI21w~~/AAUBzwA~/RgRmfbURP0RJaHR0cHM6Ly9kb2NzLm5naW54LmNvbS9uZ2lueC9hZG1pbi1ndWlkZS9sb2FkLWJhbGFuY2VyL2h0dHAtbG9hZC1iYWxhbmNlclcDc3BjQgpkkREwm2TECMaQUiN2aW5pY2l1cy5naWxlcyt0ZXN0QG1lc3NhZ2ViaXJkLmNvbVgEAAAAAA~~ HTTP/2
> Host: click.redlabs.shop
> user-agent: curl/7.79.1
> accept: */*
>
< HTTP/2 302
< content-type: text/plain
< location: https://docs.nginx.com/nginx/admin-guide/load-balancer/http-load-balancer
< server: msys-http
< x-robots-tag: noindex
< accept-ranges: bytes
< date: Tue, 27 Jun 2023 18:54:37 GMT
< via: 1.1 varnish
< age: 66
< x-served-by: cache-cgh11176-CGH
< x-cache: HIT
< x-cache-hits: 1
< x-timer: S1687892077.292871,VS0,VE38
< content-length: 0
<
* Connection #0 to host click.redlabs.shop left intact

Given this, I updated the guide to mention the absolute need for the Override host option to be off as the Host must be forwarded to SparkPost.

How To Test or Verify

• Run it locally and make sure the updates are there

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[lucas-mitri-messagebird]

This looks great!

[NupurKulkarni1]

Verified new screenshots by running locally. LGTM!

[NupurKulkarni1]

nitpicky - Give your service a name in the Options menu by clicking Edit service name.

[gilesv]

Done