Add a sensible template for Java

[paramsiddharth]

Add a new template for Java

Resolves #68: Add a sensible default template (Java)

Modifications

• Replaced the default Java template with a more regular template used in Java console programmes.
• Added throws Exception to the main method so that exceptions in general are thrown for any library/module used.

  ...
  public static void main(String[] args) throws Exception {
  ...

• Name the class "Solution" by default.
• Initialize BufferedReader and Scanner objects for input operations.

Additional Points

• A comment has been added asking the user to change the class name as needed. This may later be modified to name the classes by problem identifiers.
• Import statements for generally used libraries have been added. This would be the Java equivalent of bits/stdc++.h in competitive programming, though some prefer having their own customized fast I/O setup.

[ankushbhardwxj]

@paramsiddharth - Looks good ! Thanks