(Improvement) Add Pruning Strategy Configuration Guide to Validator Node Documentation

[3xz1]

Description:
In the current documentation, the hardware recommendations mention pruning strategies for the consensus and ParaTime states, but there's no detailed guide on how to configure these pruning strategies.

References:

• In hardware-recommendations.md, it states:

  "To enable pruning of the consensus state, set the consensus.prune.strategy and consensus.prune.num_kept parameters appropriately in your node's configuration.
  To enable pruning of the ParaTime state, set the runtime.prune.strategy and runtime.prune.num_kept parameters appropriately in your node's configuration."

• However, the pruning strategies themselves are not explained in this section, and there is no clear guidance on where to place these parameters within the node's configuration file.

Suggestion:
I would like to recommend the following improvements to the documentation:

1. Add a new section dedicated to Configuration, which can explain pruning strategies and other common settings. This section could provide clarity on where to define consensus.prune.strategy and runtime.prune.strategy, and what options are available (e.g., keep_n, default).

2. If adding a new section is not ideal, consider including a small guide in the Validator Node configuration chapter (linked here) that explains pruning strategies in detail. This could also help users understand the correct placement of these parameters.