Consider removing line about Rucio core code from the Policy package docs

[rdimaio]

The policy package documentation mentions:

documentation/docs/operator/policy_packages.md

Lines 113 to 119 in 5a8b74a

	- Before the algorithm is called for the first time, the core Rucio
	code should call `rucio.common.utils.register_policy_package_algorithms`
	to import the algorithms for this class from the policy package and
	store them in its internal dictionary. This function takes care of
	the complexities of interfacing with the policy package, such as
	importing the package if necessary, and dealing with multiple
	packages in multi-VO Rucio installations.

I don't think this should be in the docs. This is information about the implementation of the policy package logic, which seems unnecessary in the context of Adding a new algorithm class for operators

[jamesp-epcc]

This possibly shouldn't be in the operator docs - it's intended to describe how to add an entirely new class of algorithms to policy packages (taking something that was previously done by the Rucio core code and making it available as an algorithm that policy packages can customise). This does require changing the core Rucio code to make the call as described. I put it there so that it would be with the other policy package information but maybe there is a better place for it.

[rdimaio]

Sidenote: rucio.common.utils.register_policy_package_algorithms doesn't exist anymore