Add consolidated collection management script

[georgiaschafer]

Adapted from existing scripts. Optimizes functionality compared to original scripts by reducing calls to bw for each user/collection.
Creates collection for new users, assigns Administrator group to all collections, moves collections created at the root to nest under the first user with permissions.

[fer]

@georgiaschafer thank you very much for your submission, we do appreciate contributions to this repository.

Here some general comments before approving your suggestions:

• We've been recently writing a more consistent script header, including .SYNOPSIS, .DESCRIPTION, .PARAMETER, .EXAMPLE, and/or .NOTES. Although not every script is aligned with this guideline, we'd definitely like to be able to parse this information in the future to potentially generate documentation around the scripts. Please note the .EXAMPLE section is useful for the end user to run the script properly (Show 1: dry-run, 2: full recursive write, 3: filtered root run).
• Also, as file name convention, we now use InfiniteActionVerb-FunctionChange.ps1(eg., Apply-NestedPermissions.ps1)
• Although we provide different ways to securely consume secrets as client_id / client_secret by encrypting them and persisting them in file, PowerShell offers a SecureString parameter option which already saves this step.
• Check for existing BW_SESSION before Login, also avoid unnecessary prompts; reuse active sessions if present.
• It'd be great to parameterize collection discovery depth, either recursively or by defining a MaxDepth parameter.
• Using ConvertTo-Json will make the code more compact.

Don't hesitate to reach out with your thoughts and thank you very much again!

[georgiaschafer]

@fer thanks for the feedback!

1. Added the script header as requested with different examples.
2. Updated the file name to fit format.
3. This script isn't meant to be run manually; it is meant to be run by a scheduled task. This means the secrets do need to be stored in the encrypted files. I believe I have taken care to clear the secrets immediately after they are used.
4. Added code to check bw status, but I have not found a reliable way to check for an active BW_SESSION. Again, since this is meant to be run by automation and the script clears existing sessions at the end, there should not be an active session. In the event an active session does exist, no code breaking errors occur by creating a new one.
5. Depth is not in scope for this script. It is meant to add the Admin group as an owner to all collections nested within the "Users" base collection.
6. Looking at using ConvertTo-Json next update.