Improvements to the FHI for enabling further use cases

These changes to the FHI were primarily thought to enable the integration of the intel ACC ( !3344 (merged) ) in parallel of the FHI.
I preferred to make a separate MR because I believe this topic is orthogonal enough to be handled separately and because I wanted to bring even further improvements.
The improvements that it actually brings are:

1. Enable compiling and running xran F release with DPDK 21+
2. Enable including a BBDEV device in addition of the ethernet device for the FHI when performing EAL init, which is necessary for using the intel ACC with the FHI.
3. Fix an issue in usage of pkgconfig in xran E and F release. This enables to reliably build xran with the version of DPDK requested to pkgconfig while before this fix xran was always selecting the headers installed in /usr/local.

TODO:

• Include the patch to use only the public xran API.
• Testing T2 + FHI couldn't be done yet as the FHI setups at INRIA were out of order on 30th June 2025 due to a synchronization issue.