[Android] Naming refine for packaging tool

First, the new w3c manifest spec requires accepting any string to be application name.
However in previous make_apk process, they were treated as invalid input.
Second, in the past time, this part of logic is always buggy and
each sub process is validating and modifying the name passed by.
It's a good time to consolidate all these codes and validate the name at beginning,
to produce all necessary strings (transferred from the input name)
for all purposes during the make apk process.
Remove all non-alphabetic characters.
e.g. `my_first_app' => 'Myfirstapp' or 'MyFirstApp'(better).