Remove code smells and improve test coverage

[momo1606]

Refactored code to remove various Implementation and Design smells from various files and improved test coverage.
Added 6 new unit tests -
JSONSignalStoreTest (4 tests)
SegmentInputStreamTest (2 tests)

Refactoring Techniques used to remove smells and improve readability-

1. Class name - NoiseInputStream
   Method - readDecryptedSegment
   Used explaining variable to remove Magic Number

2. Package - nl.ben221199.wapi
   Class - JSONSignalStore
   Method - getJSON
   Cyclomatic complexity of the method is 10
   Refactored using Extract Method to remove Complex Method smell

3. Refactoring - Rename method/variable
   Package - com.southernstorm.noise.crypto
   Class- NewHope
   Method name - f() and g()
   From line- 539
   Smells removed - Magic Number

4. Refactoring- Decompose Conditional
   Package - com.southernstorm.noise.protocol
   Class- HandshakeState
   Method- fallback
   Method Line- 632
   The conditional expression (action != FAILED && action != READ_MESSAGE) || !localEphemeral.hasPublicKey() is complex.
   And the conditional expression (action != FAILED && action != WRITE_MESSAGE) || !remoteEphemeral.hasPublicKey() is
   complex.

5. Refactoring - Pull-up method/variable
   Package- nl.ben221199.wapi.fun.token
   Class 1- ShortList
   Class 1 method line - 9
   Class 2- LongList
   Class 2 method line - 9
   Both the classes extend the class AbstractList, and no other class extends AbstractList. There is a variable ‘length’ in
   both the subclasses ShortList and LongList which can be taken common into the AbstractList class.

6. Refactoring- Replace conditional with polymorphism
   Package - nl.ben221199.wapi
   Class- Verification
   Method- calculateToken
   Method Line- 115
   The method has a switch statement that calculates a token based on the specified platform in the Verification class. This
   code violates the open/closed principle, as adding support for a new platform requires modifying the existing code.

7. Refactoring - Extract Class
   Package - nl.ben221199.wapi
   Class- Connection
   The Connection class exhibits the multifaceted abstraction smell. It combines several responsibilities related to
   establishing a connection and performing a handshake. Additionally, it handles different types of handshakes (XX, IK) and
   fallback scenarios, leading to increased complexity. To address this smell, I refactored the Connection class by applying
   the Single Responsibility Principle (SRP) and Extract Class technique. Each responsibility (connection management,
   handshake) should ideally be encapsulated within its own class.
   I refactored the code into two separate classes: “HandshakeManager” and “Connection”. The code is now more modular,
   making it easier to understand, test, and maintain.