feat(thoth): store a thoth client in a context

Signed-off-by: Xe Iaso <me@xeiaso.net>

internal/thoth/context.go

@@ -0,0 +1,14 @@
+package thoth
+
+import "context"
+
+type ctxKey struct{}
+
+func With(ctx context.Context, cli *Client) context.Context {
+	return context.WithValue(ctx, ctxKey{}, cli)
+}
+
+func FromContext(ctx context.Context) (*Client, bool) {
+	cli, ok := ctx.Value(ctxKey{}).(*Client)
+	return cli, ok
+}