Create user settings panel to configure whether users receive notifications via text, email, or both

[ctrepka]

Current Behavior

• If a user subscribes with email only, they will receive only email alerts
• If a user subscribes with both email and phone number, they will receive only text/sms alerts
• If a user subscribed before 7/14/23, they will receive only text/sms alerts

Desired Behavior

• Users should be afforded the choice to update their alert delivery settings to either text/sms, email, or both no matter the date or mode of subscription
• Users who subscribed without a phone number should be able to add a phone number to their account
• These modifications should be accessible via map.texasflood.org in the "My Gage Alerts" panel

[L-Har]

Is this still applicable after the rewrite @ctrepka