Add option to hide code cell in Jupyter notebooks

[bcwu]

Add option to hide code cells when rendering Jupyter notebooks

Description

This commit adds requested feature to hide code cells when rendering Jupyter notebooks.

Usage example

After setting up Connect and rsconnect-python, the user can render a Jupyter notebook without its corresponding code cells by passing the '--hide-all-input' flag through the rsconnect cli:

rsconnect deploy notebook \
    -n server \
    -k APIKey \
    --hide-all-input \
    hello_world.ipynb

To selectively hide the input of cells, the user can add a tag call 'hide_input' to the cell, then pass the ' --hide-tagged-input' flag through the rsconnect cli:

rsconnect deploy notebook \
    -n server \
    -k APIKey \
    --hide-tagged-input \
    hello_world.ipynb

[mmarchetti]

This looks good. We should hold off merging until the corresponding Connect change is ready.

[mmarchetti]

Let a couple comments but the changes look good. Please hold off on merging until we are ready.