Display daily returns as bar chart with color=red for negative return…

[LarsKarbach]

…s and color=green for positive return

Description

The displayed daily return as given by the dret_chart command is implemented as a connected line chart. I think a bar chart is more visually appealing. I've gone further and added red/green color for returns below/above zero. See example:

Before:

After:

[jmaslek]

This definitely looks a lot nicer!

One question, instead of using red/green, can we use the custom theme files?

They are:

from openbb_terminal.config_terminal import theme

Then it is theme.up_color or theme.down_color instead of red/green

[LarsKarbach]

Of course, fixed it.

[jmaslek]

Nice! The linter is now yelling. Running black ./ should fix the file and make it happy.