ASoC: SOF: ipc4/Intel: Support for loading external libraries

[ujfalusi]

Hi,

In IPC4 all DSP loadable executable is a 'library' containing modules. The main or basefw is also a library which contains multiple modules.
IPC4 allows to use loadable libraries to extend the functionality of the booted basefw.

This series adds support for loading external libraries in case they are needed by the loaded topology file.

The libraries must be placed to a specific firmware directory (fw_lib_prefix), which is:
intel/avs-lib|sof-ipc4-lib/ followed by the platform name and in case of community key use a 'community' directory.
For example for upx-i11 (community key): intel/avs-lib/tgl/community is the default path.

The name of the library should be the UUID of the module it contains since the library loading is going to look for the file as <module_UUID>.bin
In case there is a need to bundle multiple modules into single library, symlinks can be used to point to the file:

module_boundle.bin
<UUID1>.bin -> module_boundle.bin
<UUID2>.bin -> module_boundle.bin
<UUID3>.bin -> module_boundle.bin

But note that in this case all modules will be loaded to the DSP since only the whole library can be loaded, not individual modules.

This PR replaces #3720 from @ranj063 and it is taking completely different route to implement the support, keeping most of the implementation IPC4 specific and not forcing artificial rules to non IPC4 users.