Rename cluster options with "stonith" in their name, and the stonith-timeout fence instance attribute, to use some derivative of "fencing" instead (for example, stonith-enabled to fencing-enabled, and stonith-max-attempts to max-fence-attempts).

• API commits to add constants for the new names
• Add the new cluster option names to cluster_options[], moving the old names to alt_name (also replace "orphan" with "removed" in the descriptions)
• Update the code to accept either name for stonith-timeout
• API commits to deprecate the old constants
• Update comment, logs, and documentation that refer to the old names
• Create a future-series task to drop support for the old names (with an XSL transform) after a suitable amount of time