Migrate set up and deployment to tag-based approach

[ebma]

Context

Subsquid introduced a new system to manage deployments. Instead of using version numbers and having a single production deployment, they want to use tags for each deployment. More info here.

Since the configuration we use currently, with designated production deployments, is deprecated and might be removed in the future, we should change our setup to support the tag based approach.

TODO

• Adjust the parameters in each manifest file
• Change the instructions of the README to describe how to publish new versions to production
• Make sure that other integrations are aware of the new tag-based endpoints. These integrations are Zenlink and the Pendulum portal.

[ebma]

@pendulum-chain/product this is a nice-to-have feature that might become important sooner or later. It's unclear when subsquid will stop supporting our current setup so the squids might break in the future.