Move bash argv opt to end of ags line in scripts (#124)

The $@ option in bash doesn't make sense to come before `generate`
because the only option we can pass before generate cli usage is `help`.

System properties can be passed via JAVA_OPTS, so there's not really a
need for any intermediaries in the command line construction.

Having $@ at the end of the arguments list allows maintainers and users
inspecting options to quickly pass new options to a script. For example,

```
./bin/aspnetcore-petstore.sh --additional-properties sourceFolder=asdf
```

For command line arguments that may appear more than once in the
arguments list, this change doesn't provide any rules about overwriting
values that may exist (hard-coded) in the script. That is, in the
example above, if aspnetcore-petstore.sh already includes the
sourceFolder set to a different value, the "winning" value is up to the
options parser and openapi-generator-cli implementation.

bin/html-markdown.sh

@@ -27,6 +27,6 @@ fi
 
 # if you've executed sbt assembly previously it will use that instead.
 export JAVA_OPTS="${JAVA_OPTS} -XX:MaxPermSize=256M -Xmx1024M -DloggerPath=conf/log4j.properties"
-ags="$@ generate -i modules/openapi-generator/src/test/resources/2_0/markdown.yaml -l html  -o samples/html.md"
+ags="generate -i modules/openapi-generator/src/test/resources/2_0/markdown.yaml -l html  -o samples/html.md $@"
 
 java $JAVA_OPTS -jar $executable $ags