Max serial number length and firmware revision length are hardcoded

[pan-apple]

Problem

#104 hardcoded the lengths to 32 bytes. This was done as ChipDeviceDescriptor is not implemented yet.

https://github.com/project-chip/connectedhomeip/blob/master/src/include/platform/ConfigurationManager.h#L62

Proposed Solution

Once a device descriptor is implemented, read these two values from its configuration.

[stale]

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

[stale]

This stale issue has been automatically closed. Thank you for your contributions.