Support Custom InitialSessionState

Use Case

As a developer leveraging the PowerShell Manager, I want to be able to preload the manager's Session State with needed options, such as (but not limited to):

• Session Configuration
• Module Import
• Variables
• Execution Policy
• Language Mode
• Startup Scripts
• Transcript Directory
• Command allow list

Describe the Solution You Would Like

Extension of the options hash for the Pwsh::Manager which allow users to specify InitialSessionState overrides from default which are implemented in the init.ps1 template file.

Something like:

options = {
  initial_session_state: {
    execution_policy: 'Unrestricted',
    import_psmodules_from_path: ['C:\path\to\foo.psd1', 'C:\path\to\bar.psd1'],
    session_configuration_file_path: 'C:\path\to\configuration.pssc'
  },
}

With a set list of supported surfaces, documentation, and testing.

Start by examining the Pwsh::Manager options handling and the init.ps1 template where default InitialSessionState behavior is implemented. Define the supported InitialSessionState surfaces from the request, then add documentation and tests covering the options and their effects. Done means callers can configure the supported session settings through the manager options.