refactor: remove Sentry integration and replace with OpenTelemetry

Remove Sentry dependencies and configuration. Introduce monitoring 
setup for OpenTelemetry. Update logging to include log format 
options, and replace Sentry error handling middleware with 
monitoring handlers for GraphQL playground. Adjust environment 
variable handling to enhance configuration clarity and flexibility.

monitoring/graphql.go

@@ -0,0 +1,41 @@
+package monitoring
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/99designs/gqlgen/graphql"
+	"go.opentelemetry.io/otel/trace"
+)
+
+func AroundOperations(ctx context.Context, next graphql.OperationHandler) graphql.ResponseHandler {
+	op := graphql.GetOperationContext(ctx)
+	spanName := fmt.Sprintf("graphql:operation:%s", op.OperationName)
+	// Span always injected in the http handler above
+	sp := trace.SpanFromContext(ctx)
+	if sp != nil {
+		sp.SetName(spanName)
+	}
+	return next(ctx)
+}
+
+func AroundRootFields(ctx context.Context, next graphql.RootResolver) graphql.Marshaler {
+	oc := graphql.GetRootFieldContext(ctx)
+	spanCtx, span := StartSpan(ctx, fmt.Sprintf("graphql:rootfield:%s", oc.Field.Name))
+	defer span.Finish()
+	return next(spanCtx)
+}
+
+func AroundFields(ctx context.Context, next graphql.Resolver) (res any, err error) {
+	oc := graphql.GetFieldContext(ctx)
+	var span Span
+	if oc.IsResolver {
+		ctx, span = StartSpan(ctx, fmt.Sprintf("graphql:field:%s", oc.Field.Name))
+	}
+	defer func() {
+		if span != nil {
+			span.Finish()
+		}
+	}()
+	return next(ctx)
+}