docs: Improve SMS API javadocs

[SMadani]

As well as tidying up the documentation for classes in the com.vonage.client.sms package, this PR refactors BinaryMessage to use a Formatter for converting the message into a hexadecimal string, thus removing the dependency on commons-codec and reducing the SDK's footprint. This is still used in tests to verify correctness.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.00%. Comparing base (fe06b81) to head (4aedf7b).
Report is 75 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #558      +/-   ##
============================================
+ Coverage     95.60%   96.00%   +0.40%     
- Complexity     3427     3755     +328     
============================================
  Files           513      564      +51     
  Lines          8141     8707     +566     
  Branches        451      498      +47     
============================================
+ Hits           7783     8359     +576     
+ Misses          198      175      -23     
- Partials        160      173      +13     

Files with missing lines	Coverage Δ
...main/java/com/vonage/client/sms/MessageStatus.java	100.00% <ø> (ø)
...c/main/java/com/vonage/client/sms/MessageType.java	100.00% <ø> (ø)
src/main/java/com/vonage/client/sms/SmsClient.java	100.00% <ø> (ø)
...a/com/vonage/client/sms/SmsSubmissionResponse.java	80.00% <ø> (ø)
...onage/client/sms/SmsSubmissionResponseMessage.java	100.00% <ø> (ø)
.../com/vonage/client/sms/messages/BinaryMessage.java	90.00% <100.00%> (+3.33%)	⬆️
...n/java/com/vonage/client/sms/messages/Message.java	100.00% <100.00%> (ø)
...va/com/vonage/client/sms/messages/TextMessage.java	100.00% <ø> (ø)

... and 111 files with indirect coverage changes