[Access] Refactor REST Routes Package

[UlyanaAndrukhiv]

Closes: #6615

Context

This PR introduces a significant restructuring of the access/rest folder, enhancing modularity and clarity.

• The new organization separates http and WebSocket components into http and WebSockets directories, simplifying maintenance and readability.
• Common functionality is moved to the rest/common package.
• RouterBuilderimplementation is separated from all routes and moved to rest/router.
• Lists of http and ws routes are now in http_routes.go and ws_routes.go, respectively.
• The current v1/subscribe_events route is moved into the websocket/legacy folder to separate future WebSocket implementations.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 35.79%. Comparing base (899e12e) to head (5065c78).

❗ There is a different number of reports uploaded between BASE (899e12e) and HEAD (5065c78). Click for more details.

HEAD has 22 uploads less than BASE

Flag	BASE (899e12e)	HEAD (5065c78)
unittests	30	8

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #6616       +/-   ##
===========================================
- Coverage   41.20%   35.79%    -5.42%     
===========================================
  Files        2052      393     -1659     
  Lines      182191    34996   -147195     
===========================================
- Hits        75075    12527    -62548     
+ Misses     100824    21362    -79462     
+ Partials     6292     1107     -5185     

Flag	Coverage Δ
unittests	35.79% <ø> (-5.42%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.