Enable wbi for offline setups of Workbench

[tnederlof]

The current scope of wbi is to configure Workbench in an online environment. Some customers need to install Workbench in an offline environment which presents some unique challenges. Ideally wbi would be able to function both online and offline. Outlining some areas that need to be considered on how to handle.

Workbench install - wbi can be setup to install Workbench automatically but in the case of offline the user will need to upload manually to the server. Need to make sure a user doesn't try to install and have the network hang.

R install - wbi can be setup to install R versions automatically but in the case of offline the user will need to upload manually to the server. Need to make sure a user doesn't try to install and have the network hang.

Python install - wbi can be setup to install Python versions automatically but in the case of offline the user will need to upload manually to the server. Need to make sure a user doesn't try to install and have the network hang.

Jupyter - setup requires access PyPI to setup which can be tricky if you don't have internet access (need to make sure your have RSPM accessible or an alternative PyPI source in network).

License activation - currently asks for a license key and activates over the internet. Would need to add capacity for license file and/or offline activation.

Package manager - currently wbi checks for connectivity to package manager, this is helpful to make sure networking is setup correctly. Need to not bother with Posit Public Package Manager though.

[samcofer]

Based on our conversation earlier today, we discussed the following things:

1. Splitting out the check for whether or not we are running online into a separate issue since it's low-hanging fruit
   WBI should check for outbound internet connectivity and fail if offline #179
2. Add a CLI flag to setup/install as ---offline as a boolean to indicate that wbi is being run offline
3. Edit the error message from WBI should check for outbound internet connectivity and fail if offline #179 to indicate that if the customer intends to be offline, they should rerun the wbi setup program with the --offline flag. Add a note that indicates the new requirements that will be in place:
   a. Local folder including all installation files appropriate for the current OS
   b. A source of Python packages, either PackageManager or some other URL.
4. When wbi is run with the --offline argument, wbi should request the folder path to the customer's installation files, index those files, and confirm with the user the installation files we've found.
5. Next, it should prompt for the URL for a source of Python packages, then check the URL to validate that it's a valid repository of Python packages
6. Following steps in the setup should ask if the languages should be installed and then should auto-install the downloaded versions that match the particular language.
7. License activation should be skipped and a message should be printed at the end of the installation to direct users to activate their license using the appropriate offline activation method with a link.