Add support for a styled-value datatype

[okennedy]

What pain point is this feature intended to address? Please describe.
One of the nice features of spreadsheets is the ability to display conditional formatting. Presently, Vizier has no way to highlight cells based on some properties.

Describe the solution you'd like
Simple Version

• Add a UDT that signifies string + css (limited features only)

Specific style choices:

• Background color
• Text color
• Italics
• Text weight

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.