feat: optimize queue usage for follow endpoints

[Malaydewangan09]

What changes are being made and why?

This PR introduces improvements to the follow endpoints for executions and logs in Kestra. It focuses on optimizing queue usage to enhance scalability and resource efficiency.

Key Changes:

Centralized Queue Management:

Implemented a singleton ExecutionStreamingService to manage a single queue consumer for all execution updates.
Reduces the creation of multiple queue consumers and threads for each connection.
Subscriber Pattern:

Introduced a subscription mechanism where clients (UI connections and wait=true executions) register as subscribers for specific execution IDs.
Updates are selectively broadcasted to relevant subscribers using a ConcurrentHashMap.

Addresses #6777

[loicmathieu]

Hi @Malaydewangan09 this looks good at first look! Great implementation.
I'll review it next week or the week after and made adjustment if necessary as this is a very complex area and prone to memory leak (due to how SSE connections work).

Thank you.

[Malaydewangan09]

Sure, @loicmathieu
Thanks!