feat(idm): update CHD to source static and dynamic list input from the input context

[mjreno]

No description provided.

[langevin-usgs]

This looks good, @mjreno. Nice to see this all settling in.

[mjreno]

@langevin-usgs I'm thinking about adding CHD updates to this PR if you aren't opposed to it. Without some initial package there are some missing variables in the dfn2f90 generated code that the BoundaryPackage extensions refer to.

[langevin-usgs]

Sure, I say go for it. This PR is pretty small in it's current form, so the CHD additions make sense here.

[mjreno]

This PR introduces extensions to the BndModule (BoundaryPackageExt.f90) to support integrating base stress packages with IDM:

• BndExtType, which extends BndType, as a new base type for stress packages that want to integrate with IDM.
• CHD (gwf3chd8.f90) refactored to inherit from BndExtType

This PR reflects changes in approach to managing bound parameters that were outlined in PR #1337, including:

• IDM allocates and loads based on dfn described parameters (e.g. head), it does not for example aggregate parameters into a 2d bound array
• In general, IDM tries to represent input as provided from the user. For example, with list based inputs IDM reads and stores cellids. A cellid is translated to a node (user or reduced) on the model side. The BndExtType contains a member cellid that points to the input context.
• Timeseries and TAS are managed on the input side
• No auxiliary multipliers or flow (cell area) calculations are done on the input side- this is managed on the model side.
• While certain parameters may be updated through a copy to the model side (e.g. nbound copied via mem_set_value()), many arrays are intended to be pointed to directly from the model side.

Additional PR details:

• Some refactoring to package input mempath was done for consistency with respect to how mempaths are managed and also transparency in package code.
• An IDM function was added to return a FILEIN input file name when a maximum of one input file is expected.
• BndExtType defines a read and prepare routine that translates cellids to node numbers.
• Logging is supported (similar to ListReader) but requires packages to implement a routine that can return a value for a bound parameter. CHD implements this routine (bound_value()).