Add support for user-specified instance or namespace configuration at installation-time

[isc-eneil]

Per conversations with HSOPS, we are asking for a single command that can install/load a module into a namespace and then perform configuration in that namespace based on a user-provided "env" file that provides a better structure than lots of -D arguments.

[isc-tleavitt]

Use case is user-provided info for application installation time:

install packagename -verbose -env /path/to/env.json

We'll load env.json into params("env") as a %Library.DynamicObject which can then be referenced everywhere meaningful.

[isc-tleavitt]

Need to support multiple files with the objects merged (use case: non-secrets and secrets)

[isc-tleavitt]

As part of this, need to fix Invoke getting access to the params array.

[isc-tleavitt]

To get access to the params array, we'll make a singleton (probably %IPM.General.InstallContext) API and have params available there. (I'm not sure if there's already a singleton with params?)