refactor(ffmpeg): generalize device and hardware support for multiple OS

- Rename `device_freebsd.go` to `device_bsd.go` and `hardware_freebsd.go` to `hardware_bsd.go` to reflect broader BSD support (FreeBSD, NetBSD, OpenBSD, Dragonfly).
- Update build tags in `device_bsd.go` and `hardware_bsd.go` to include FreeBSD, NetBSD, OpenBSD, and Dragonfly.
- Rename `device_linux.go` to `device_unix.go` and `hardware_linux.go` to `hardware_unix.go` to generalize Unix support excluding Darwin-based systems and BSDs.
- Add specific build tags to `device_darwin.go`, `device_unix.go`, `hardware_darwin.go`, and `hardware_unix.go` to correctly target their respective operating systems.
- Ensure Windows-specific files (`device_windows.go` and `hardware_windows.go`) are correctly tagged for building on Windows.

internal/ffmpeg/device/device_bsd.go

@@ -1,3 +1,5 @@
+//go:build freebsd || netbsd || openbsd || dragonfly
+
 package device
 
 import (

internal/ffmpeg/device/device_darwin.go

@@ -1,3 +1,5 @@
+//go:build darwin || ios
+
 package device
 
 import (

internal/ffmpeg/device/device_unix.go

@@ -1,3 +1,5 @@
+//go:build unix && !darwin && !freebsd && !netbsd && !openbsd && !dragonfly
+
 package device
 
 import (

internal/ffmpeg/device/device_windows.go

@@ -1,3 +1,5 @@
+//go:build windows
+
 package device
 
 import (

internal/ffmpeg/hardware/hardware_bsd.go

@@ -1,3 +1,5 @@
+//go:build freebsd || netbsd || openbsd || dragonfly
+
 package hardware
 
 import (

internal/ffmpeg/hardware/hardware_darwin.go

@@ -1,3 +1,5 @@
+//go:build darwin || ios
+
 package hardware
 
 import (

internal/ffmpeg/hardware/hardware_unix.go

@@ -1,3 +1,5 @@
+//go:build unix && !darwin && !freebsd && !netbsd && !openbsd && !dragonfly
+
 package hardware
 
 import (

internal/ffmpeg/hardware/hardware_windows.go

@@ -1,3 +1,5 @@
+//go:build windows
+
 package hardware
 
 import "github.com/AlexxIT/go2rtc/internal/api"