Add operio-fractal to task list on doc page

[jluethi]

Let's add the new operio-fractal package available at https://github.com/leukemia-kispi/operetta-compose by @fdsteffen to the list of available tasks on the Fractal tasks doc page: https://fractal-analytics-platform.github.io/fractal-tasks-core/all_tasks/

[tcompa]

Should we also provide a description field?

[jluethi]

Let's take this description from the README initially:

Fractal tasks for the Opera/Operetta microscope and drug response profiling

[tcompa]

See https://fractal-analytics-platform.github.io/fractal-tasks-core/all_tasks/#operio-fractal