Improve portability

Improve support for RISC-V arch in volk_gnsssdr via cpu_features (updated to c919e9a).
Set BLA_PREFER_PKGCONFIG if not defined by the user, helps to find lapack in some archs (e.g., riscv64)
Fix for Fedora/OpenSUSE, which do not install cpu_features along volk.
Remove volk_gnsssdr_8ic_s8ic_multiply_8ic kernel since it was problematic in some archs
Improve Python detection
Fixes for GCC 13
Remove ENABLE_GENERIC_ARCH configuration option and old ARM detection mechanism
Update gtest to 1.13.0
Add CI jobs for volk_gnsssdr and gnss-sdr in non-x86 archs

docs/CHANGELOG.md

@@ -70,11 +70,14 @@ All notable changes to GNSS-SDR will be documented in this file.
 - Improved passing of compiler flags to `volk_gnsssdr` if the corresponding
   environment variables are defined. This fixes warnings in some packaging
   systems.
+- Improved support for the RISC-V architecture.
 - Test files are now donwloaded at configuration time instead of being included
   in the source tree. This allows for a smaller package and fixes Lintian
   `very-long-line-length-in-source-file` warnings since those files were not
   recognized as binaries. The configuration flag `-DENABLE_PACKAGING=ON` passed
   to CMake deactivates file downloading.
+- The `ENABLE_GENERIC_ARCH` building option was removed, simplifying the process
+  of buiding the software in non-x86 processor architectures.
 
 ### Improvements in Usability: