Prisma1: document connectionLimit configuration setting

[marktani]

Is your feature request related to a problem? Please describe.
There is no documentation about the connectionLimit configuration setting.

Describe the solution you'd like
All relevant information about the connectionLimit setting should be added to the docs, and ideally also in a new example.

It might be beneficial to specifically mention that the env vars like SQL_CLIENT_CONNECTION_LIMIT and SQL_INTERNAL_CONNECTION_LIMIT are not in use anymore.

Additional context
You can find some information about this here: https://github.com/prismagraphql/prisma/issues/2640

[mavilein]

The version 1.12 contains a fix for the connectionLimit setting. From this version on Prisma will use exactly the number of connections specified. However this setting must be set to at least 2. This is because we need one connection for the management API. All the remaining connections are used for the service APIs.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[mavilein]

We should still do this @nikolasburk @marktani

[marcosfede]

can you please add some docs on this? What's the default value?