feat(channels): add channel configuration page

[samuelmasse]

Adds a channel configuration page in the admin. Also adds bp.messaging to the sdk to provide http clients to make calls to messaging

Bumps messaging to 1.1.6 and adds a migration

Todo in future PRs

• Should not show the telegram webhook (or show it with / at the end)
• Add channel version field, and switch between legacy and v1 channels
• Improve fields validation, add checkboxes and textarea
• Add a way to delete a leftover channel configuration (when a bot is deleted)
• Add a way to create channel configurations without a bot
• Add a way to rename channel configurations
• Stream health events to the UI for debugging

Closes DEV-1628
Closes DEV-2474

[linear]

DEV-1628 We should regularly keep track of bots that have been deleted and unconfigure them from messaging if the were

If bots are remove but just deleting the files then they'll stay configured on messaging which isn't ideal

[samuelmasse]

Looks like this at the moment. You can configure channels for any botId. The bot id doesn't have to match an existing botId, but when it does incoming messages will be responded by that bot. This will allow transfering channel configurations from bot config to global configurations (which they are)