build: Remove CMAKE_SKIP_BUILD_RPATH and SKIP_BUILD_RPATH settings

Remove CMake settings that are no longer needed after reordering Guix build script to perform binary checks after installation.

Also removes unused CMake maintenance targets (check-security and check-symbols) and updates security checks to include libexec/ directory binaries (see PR #31679).

contrib/guix/libexec/build.sh

@@ -248,11 +248,6 @@ mkdir -p "$DISTSRC"
     # Build Bitcoin Core
     cmake --build build -j "$JOBS" ${V:+--verbose}
 
-    # Perform basic security checks on a series of executables.
-    cmake --build build -j 1 --target check-security ${V:+--verbose}
-    # Check that executables only contain allowed version symbols.
-    cmake --build build -j 1 --target check-symbols ${V:+--verbose}
-
     mkdir -p "$OUTDIR"
 
     # Make the os-specific installers
@@ -282,6 +277,13 @@ mkdir -p "$DISTSRC"
             ;;
     esac
 
+    # Perform basic security checks on installed executables.
+    echo "Checking binary security on installed executables..."
+    python3 "${DISTSRC}/contrib/guix/security-check.py" "${INSTALLPATH}/bin/"* "${INSTALLPATH}/libexec/"*
+    # Check that executables only contain allowed version symbols.
+    echo "Running symbol and dynamic library checks on installed executables..."
+    python3 "${DISTSRC}/contrib/guix/symbol-check.py" "${INSTALLPATH}/bin/"* "${INSTALLPATH}/libexec/"*
+
     (
         cd installed