[common] merge RenderBackend and ShaderBackend options (#3313)

first of all it makes UI a tad bit more simple and benefits the end user
second, it allows to add new backends a bit more easily
and also, there was a shader backend option in android... we don't use opengl in android
so may as well save ourselves the trouble, aye

![image](/attachments/c0195bca-da18-4907-9e4a-3b62c4292f1a)

Signed-off-by: lizzie <lizzie@eden-emu.dev>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3313
Reviewed-by: Maufeat <sahyno1996@gmail.com>
Reviewed-by: DraVee <dravee@eden-emu.dev>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>

src/android/app/src/main/res/values-nb/strings.xml

@@ -63,9 +63,7 @@
 
     <string name="cpuopt_unsafe_host_mmu">Aktiver verts-MMU-emulering</string>
     <string name="cpuopt_unsafe_host_mmu_description">Denne optimaliseringen fremskynder minnetilgang av gjesteprogrammet. Hvis aktivert, utføres gjestens minnelesing/skriving direkte i minnet og bruker vertens MMU. Deaktivering tvinger alle minnetilganger til å bruke programvarebasert MMU-emulering.</string>
-    <!-- Shader Backend -->
-    <string name="shader_backend_glsl">GLSL</string>
-    <string name="shader_backend_glasm">GLASM</string>
+
     <!-- NVDEC Emulation -->
     <string name="nvdec_emulation">NVDEC-emulering</string>
     <string name="nvdec_emulation_description">Velg hvordan videodekoding håndteres</string>
@@ -339,8 +337,6 @@
     <!-- Graphics settings strings -->
     <string name="renderer_resolution">Oppløsning (håndholdt/dokket)</string>
     <string name="renderer_vsync">VSync-modus</string>
-    <string name="shader_backend">Shader-backend</string>
-    <string name="shader_backend_description">Velg hvordan shadere kompileres</string>
     <string name="renderer_scaling_filter">Filter for vindustilpasning</string>
     <string name="fsr_sharpness">FSR-skarphet</string>
     <string name="fsr_sharpness_description">Bestemmer bildekvalitet med FSR</string>