Add option to select alert channel

[n-maido]

Context:
When a user submits a form, the bot sends an alert message to a specified channel (based on the given channel id). Right now, that channel is hard coded.

What you can do

• On the website, in the create form section, add a drop down to allow the user to select which channel he/she wants to send these alerts to (similar to the dropdown to select a server)
• Get the channel id and send to the backend
• You don't need to modify anything in the bot