Allow for a dynamic number of OptoHybrids

Description

Title says it all: this MR aims at retrieving the number of OptoHybrids from the firmware registers, avoiding to edit the cmsgemos code to run with some firmware flavors.

No behavioral change is expected. Performance impact is minimized by caching the value on the first successful register access.

Related Issue

How Has This Been Tested?

Tested on the GE1/1 integration setup in b904:

• Configuration
• Physics run
• Monitoring
• Calibration scan (S-curve)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.