software/ors-amarisoft: use slapos.recipe.build to create gadget folder

This was depending on a side effect of slapos.recipe.template of
creating the intermediate folder structure so that it is here for
subsequent slapos.recipe.build:download sections

Using slapos.recipe.build it is a bit more explit

software/ors-amarisoft/software.cfg

@@ -82,8 +82,17 @@ recipe  = slapos.recipe.build:download
 url     = ${:_profile_base_location_}/config/${:_buildout_section_name_}
 
 [gadget]
-recipe = slapos.recipe.template
-output = ${buildout:directory}/${:_buildout_section_name_}/renderjs.js
+# creates `gadget` folder and downloads renderjs.js
+recipe = slapos.recipe.build
+install =
+  import os
+  if not os.path.exists(location):
+    os.mkdir(location)
+  with open(self.download(options['url'], options['md5sum'])) as src, \
+      open(options['output'], 'w') as dst:
+    dst.write(src.read())
+location = ${buildout:directory}/${:_buildout_section_name_}
+output = ${:location}/renderjs.js
 url = https://lab.nexedi.com/nexedi/renderjs/raw/b715d066bfddc30bedfc8356fb720dcbb391378e/dist/renderjs-0.28.0.js
 md5sum = 7e074a29b07e0045d2ba8a8e63bd499e
 
@@ -103,7 +112,7 @@ inline =
 [copy-gadget-to-software]
 recipe      = slapos.recipe.build:download
 url         = ${:_profile_base_location_}/gadget/${:_buildout_section_name_}
-destination =  ${buildout:directory}/gadget/${:_buildout_section_name_}
+destination =  ${gadget:location}/${:_buildout_section_name_}
 
 [enb.jinja2.cfg]
 <= copy-config-to-instance