refactor(application): introduce application global state (#2072)

* start breaking up the giant channel refactor now that it's better understood - easier to merge bites

Signed-off-by: Dave Lee <dave@gray101.com>

* add concurrency and base64 back in, along with new base64 tests.

Signed-off-by: Dave Lee <dave@gray101.com>

* Automatic rename of whisper.go's Result to TranscriptResult

Signed-off-by: Dave Lee <dave@gray101.com>

* remove pkg/concurrency - significant changes coming in split 2

Signed-off-by: Dave Lee <dave@gray101.com>

* fix comments

Signed-off-by: Dave Lee <dave@gray101.com>

* add list_model service as another low-risk service to get it out of the way

Signed-off-by: Dave Lee <dave@gray101.com>

* split backend config loader into seperate file from the actual config struct. No changes yet, just reduce cognative load with smaller files of logical blocks

Signed-off-by: Dave Lee <dave@gray101.com>

* rename state.go ==> application.go

Signed-off-by: Dave Lee <dave@gray101.com>

* fix lost import?

Signed-off-by: Dave Lee <dave@gray101.com>

---------

Signed-off-by: Dave Lee <dave@gray101.com>

core/application.go

@@ -0,0 +1,39 @@
+package core
+
+import (
+	"github.com/go-skynet/LocalAI/core/config"
+	"github.com/go-skynet/LocalAI/core/services"
+	"github.com/go-skynet/LocalAI/pkg/model"
+)
+
+// The purpose of this structure is to hold pointers to all initialized services, to make plumbing easy
+// Perhaps a proper DI system is worth it in the future, but for now keep things simple.
+type Application struct {
+
+	// Application-Level Config
+	ApplicationConfig *config.ApplicationConfig
+	// ApplicationState *ApplicationState
+
+	// Core Low-Level Services
+	BackendConfigLoader *config.BackendConfigLoader
+	ModelLoader         *model.ModelLoader
+
+	// Backend Services
+	// EmbeddingsBackendService      *backend.EmbeddingsBackendService
+	// ImageGenerationBackendService *backend.ImageGenerationBackendService
+	// LLMBackendService             *backend.LLMBackendService
+	// TranscriptionBackendService *backend.TranscriptionBackendService
+	// TextToSpeechBackendService  *backend.TextToSpeechBackendService
+
+	// LocalAI System Services
+	BackendMonitorService *services.BackendMonitorService
+	GalleryService        *services.GalleryService
+	ListModelsService     *services.ListModelsService
+	LocalAIMetricsService *services.LocalAIMetricsService
+	// OpenAIService         *services.OpenAIService
+}
+
+// TODO [NEXT PR?]: Break up ApplicationConfig.
+// Migrate over stuff that is not set via config at all - especially runtime stuff
+type ApplicationState struct {
+}