debian: adapt the XML scanning logic to the new layout

[junjiemao1]

ACRN's next-gen configurator takes a path to users "work folder" and
generates all files (including the board XML and the scenario XML) of a
scenario under that folder. As a result, users maintaining multiple
scenarios for multiple boards are recommended to organize their config
files using the following layout. Note that the board and scenario XMLs
will have unified names, and the name of the folder is used as the name of
the scenario.

.
├── cfl-k700-i7
│   ├── hybrid_launch_2user_vm
│   │   ├── board.xml
│   │   └── scenario.xml
│   ├── hybrid_rt
│   │   ├── board.xml
│   │   └── scenario.xml
│   ├── partitioned
│   │   ...
│   └── shared_launch_6user_vm
│   ...
├── generic_board
│   ├── hybrid_launch_2user_vm
│   │   ├── board.xml
│   │   └── scenario.xml
│   ├── hybrid_rt
│   | ...
│   ├── ...
├── nuc11tnbi5
│   ├── ...
└── ...

This patch adjusts the XML scanning logic (namely the get-xml-data macro)
in debian/rules so that it can scan BOTH the current layout AND the
recommended one above. Some recent changes are also taken into
consideration:

• Scenario XMLs no longer have the board and scenario attribute at
  its root node. The new scanning logic infers as follows.

  • If a scenario XML contains a board attribute, it will be used. Otherwise
    other XML files under the same directory will be scanned for that board
    attribute and the first found will be used, assuming new scenario XMLs for
    different boards are not placed under the same directory.

  • The scenario name is the file name (without the .xml suffix) if it is not
    "scenario". Otherwise the work folder name will be used.

• Symbolic links are ignored to avoid duplicate builds.

• Launch XMLs are now merged into scenario XMLs. So it is no longer
  necessary to distinguish scenario XMLs from launch ones.

Signed-off-by: Junjie Mao [email protected]