Support sending standardized uuid and priority values

[yevhenii0]

Context

Extend TkmsMessage to have two new methods:

new TkmsMessage()
  .setTopic(...)
  .setValue(...) 
  .addUuidHeader(...)     // <- NEW (x-wise-uuid)
  .addPriorityHeader(...) // <- NEW (x-wise-priority)

Both values enable efficient message pre-processing on consumer side.

Checklist

• Change meets or does not compromise the Baseline Security Requirements

[yevhenii0]

@tw-peeterkarolin I have patched pr to

• Not require uuid header presence.
• Directly manipulate headers instead of having fields on the message.