Add Access Sequence support to `pack:` `path:`

[ReinhardKeil]

The Problem To Be Solved

This does currently not work:

  packs:
    - pack: PyTorch::ExecuTorch
      path: $SolutionDir()$/packs/PyTorch.ExecuTorch.1.1.0-rc1-build.12

It fails with the message:

pack path: C:/w/ModelNova/RockPaperScissors/AppKit-E8_USB/ai_layer/$SolutionDir()$/packs/PyTorch.ExecuTorch.1.1.0-rc1-build.12 does not exist

Test Project: https://github.com/Arm-Examples/modelnova

Suggest A Solution
Enable Access Sequences in pack: path: node.

CMSIS-Toolbox 2.13

[jkrech]

Probably it is worth reviewing where access sequnces shall be supported.
The current list of nodes is documented here:
https://open-cmsis-pack.github.io/cmsis-toolbox/YML-Input-Format/#access-sequences

[brondani]

Probably it is worth reviewing where access sequences shall be supported.

Note that variables only expand $SolutionDir()$ access sequences.
I would propose to do the same here to keep it simple if it's enough for this use case.
Expanding access sequences such as $Bname$ or $Dname$ before loading packs would be error-prone and/or require increased complexity.

Please also note the pack's path in the mentioned ModelNova is not under the solution root (which is the csolution.yml folder) but it is out of tree:

  packs:
    - pack: PyTorch::ExecuTorch
      path: ../../packs/PyTorch.ExecuTorch.1.1.0-rc1-build.12

[ReinhardKeil]

The issue is not urgent. It was just an observation.