chore: drop gpt4all.cpp (#3106)

chore: drop gpt4all

gpt4all is already supported in llama.cpp - the backend was kept for
keeping compatibility with old gpt4all models (prior to gguf format).

It is good time now to clean up and remove it to slim the compilation
process.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

pkg/model/initializers.go

@@ -45,11 +45,6 @@ const (
 
 	LLamaCPPGRPC = "llama-cpp-grpc"
 
-	Gpt4AllLlamaBackend = "gpt4all-llama"
-	Gpt4AllMptBackend   = "gpt4all-mpt"
-	Gpt4AllJBackend     = "gpt4all-j"
-	Gpt4All             = "gpt4all"
-
 	BertEmbeddingsBackend  = "bert-embeddings"
 	RwkvBackend            = "rwkv"
 	WhisperBackend         = "whisper"
@@ -144,11 +139,10 @@ ENTRY:
 
 	// sets a priority list - first has more priority
 	priorityList := []string{
-
 		// First llama.cpp(variants) and llama-ggml to follow.
 		// We keep the fallback to prevent that if the llama.cpp variants
 		// that depends on shared libs if breaks have still a safety net.
-		LLamaCPP, LlamaGGML, Gpt4All, LLamaCPPFallback,
+		LLamaCPP, LlamaGGML, LLamaCPPFallback,
 	}
 
 	toTheEnd := []string{
@@ -434,9 +428,6 @@ func (ml *ModelLoader) BackendLoader(opts ...Option) (client grpc.Backend, err e
 	var backendToConsume string
 
 	switch backend {
-	case Gpt4AllLlamaBackend, Gpt4AllMptBackend, Gpt4AllJBackend, Gpt4All:
-		o.gRPCOptions.LibrarySearchPath = filepath.Join(o.assetDir, "backend-assets", "gpt4all")
-		backendToConsume = Gpt4All
 	case PiperBackend:
 		o.gRPCOptions.LibrarySearchPath = filepath.Join(o.assetDir, "backend-assets", "espeak-ng-data")
 		backendToConsume = PiperBackend