Warn when users reload with options that aren't going to be applied

If a user does `consul reload` and changes parameters that aren't reloadable we should issue a warning to the log. Otherwise, things can get pretty confusing for users. This is the list of reloadable parameters:

https://www.consul.io/docs/agent/options.html#reloadable-configuration

This came up on #1225 where a user was trying to update their DNS TTLs. Those could actually be reloaded pretty easily, but in general it would be a good user experience to tell them that not all changes got applied in the reload. This would also be pretty easy to do by comparing the two configs minus the reloadable parts and noting any differences.

Start with the reloadable configuration list in the linked Consul agent documentation and trace the handling of `consul reload`. Compare the previous and new configurations while excluding reloadable parameters, and consider the work done when a reload logs a warning for remaining changes that were not applied.

Written by the indexing model from the issue text.