... for use in the y-axis text of charts

Move creation of the combined names + symbols array to the if/else
block

- Create a copy of the array passed in as an argument, which will be
modified in place

- Replace 'forEach' method with 'filter' method for brevity

Check the length of the correct array

Refactor the logic for creating the metadata for the temperature
difference (dT, VL-RL) of a single building into a new function

Refactor the logic for calculating the timestamps & values for the
temperature difference (dT, VL-RL) of a single building into a new
function

We were using the original VL observations array in the 'map' array
method. Updated to use the final version of VL observations array

Confirm that the selected drop-dowwn options are valid before fetching
the observations

Create a full title for line and column charts.

Ensure that title contains all the selected data points when
aggregation is selected. Before this fix, only the first data point
was included

Function uses options from drop-down list that have been selected by a
user to populate the appropriate observations and then draw the
appropriate chart

Add two new aggregation type strings. Now there a four supported
aggregation type strings

These functions wrap the logic of the two functions that calculate the
minimum or maximum observation values for an interval delimited by
calendar dates as well as delimited by calendar months

Calculate the minimum and maximum of observation values for a monthly
interval

Calculate the minimum and maximum of observation values for a daily
interval

It is assumed that this chart type will be used for visualizing
aggregated results