Introduce support for new VM based minicap to support Android 12

This commit introduce a new option to use a new minicap
implementation by specifying --screen-grabber or the env
variable SCREEN_GRABBER. The current native minicap is the default
and is refered as 'minicap-bin'. The new minicap which is packaged
in an apk is usable with 'minicap-apk' and will be used as a
fallback.
At the moment, this apk is expected to be included in
minicap-prebuilt node package at this location
minicap-prebuilt/prebuilt/noarch/minicap.apk.

STFService.apk has also been updated to take into account Android 12

Signed-off-by: Crepieux Pierre <pierre.crepieux@orange.com>

lib/util/pathutil.js

@@ -23,15 +23,24 @@ module.exports.module = function(target) {
 }
 
 // Export
-module.exports.requiredMatch = function(candidates) {
+module.exports.match = function(candidates) {
   for (var i = 0, l = candidates.length; i < l; ++i) {
     if (fs.existsSync(candidates[i])) {
       return candidates[i]
     }
   }
-
-  throw new Error(util.format(
-    'At least one of these paths should exist: %s'
-  , candidates.join(', ')
-  ))
+  return undefined
+}
+
+// Export
+module.exports.requiredMatch = function(candidates) {
+  matched = this.match(candidates)
+  if(matched !== undefined) {
+    return matched
+  } else {
+    throw new Error(util.format(
+      'At least one of these paths should exist: %s'
+    , candidates.join(', ')
+    ))
+  }
 }