Add ipysheet support (Jupyter widget for tabular data)

[giswqs]

Add support for ipysheet within Colab.

@blois @martinRenou @SylvainCorlay @maartenbreddels

Is your feature request related to a problem? Please describe.
When working with tabular data, there is often a need to change the cell values interactively and save the results as a Pandas DataFrame or a file. ipysheet is well suited for this. I tried the follow code on install ipysheet in Colab. The spreadsheet does not show up.

from google.colab import output
output.enable_custom_widget_manager()

import ipysheet
sheet = ipysheet.sheet()
sheet

Describe the solution you'd like
Provide a way to install and use the third-party jupyter widget ipysheet. A good test case would be the ability to run the following example and display the spreadsheet in Colab. More examples can be found here.

import ipysheet
sheet = ipysheet.sheet(rows=3, columns=4)
cell1 = ipysheet.cell(0, 0, 'Hello')
cell2 = ipysheet.cell(2, 0, 'World')
cell_value = ipysheet.cell(2,2, 42.)
sheet

Describe alternatives you've considered
N/A

Additional context

• ipysheet documentation: https://ipysheet.readthedocs.io/
• ipysheet binder:

[martinRenou]

This might be due to jupyter-widgets-contrib/ipysheet#208