Fix Confusion Related to Time Zones

Some of our users are confused by the "Local System Time" option in the settings panel. This option displays the time of all earthquakes using the user's current time zone. Some people are confused about the word "Local" and assume that this means we are displaying the local time in which the event occurred.

Update:

• Update "Local System Time" label to "User Time Zone"
• Add the (UTC-XXX) offset as an indication of what the user is selecting. Similar to how UTC offset is displayed for the Auto Update option.
• Add documentation to help section that explains what "User Time Zone" indicates, and that the time zone can be set incorrectly by users.
• Add link from timezone settings into the documentation.
• Use <abbr> to spell out "Coordinated Universal Time" for the UTC time zone option
• We are using setHelpSection and showHelpSection interchangeably. Clean this up to always use setHelpSection. That means you need to update the actions that are being dispatched, and update anywhere that an event is being emitted as showHelpSection for consistency.
• Fix broken help link in settings panel "read more" link at top of earthquake section.