cutadapt.config: add config file for docker

src/nf_test.config

+docker {
+  temp = 'auto'
+  enabled = true
+}
+
+process {
+  $adaptor_removal {
+    container = "cutadapt:1.14"
+  }
+}
+
+process {
+  $trimming {
+    container = "cutadapt:1.14"
+  }
+}