[Feature] Add extra SNS Subscription types: Get alerts for SMS (text) and/or https (webhooks) too

**Is your feature request related to a problem? Please describe.**
I did email first because it was easy/cheap, and got us off the ground. Now that the project is farther along and we know what exactly we alert, look into supporting more than just email.

- **Text** would be nice, but since you have to rent a number, might cost a lot. It's possible you can't use cdk because of that too. I haven't looked into it really yet, so it'll require research.
- I feel like **https** wouldn't cost much, and might mean support for people to add to a discord server and not need to get all their friends numbers/emails for alerts then.

**Describe the solution you'd like**
If cheap, both SNS and https protocol options added for support.

**Describe alternatives you've considered**
Just keep it as is, email is "good enough". Seems like this could be very useful for people, without adding really any complexity to the code-base though.

**Additional context**
- [SNS Subscription CDK docs](https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_sns.SubscriptionProtocol.html)