Create Endpoint to determine if user gets or not in the Experiment

[freddyucv]

(We need a name for this end point)

This end point is going to do:

• Determine if the visitor must go into the experiment: using the traffic allocation.
• If the user is going to be included into the experiment, then the end point has to determine which variant it is going to use.
• Should create the experiment cookies, this cookies set if the user was already include into a experiment or not.

This code can be a guide to implement this end point

https://github.com/dotCMS/core/pull/22626/files#diff-c9ae118362481edfb5d2482921d806d94f8bbcc145018380401a9d70ad75fb69R155

Acceptance Criteria:

• Crate the end point and any util need it
• Make postman test

[freddyucv]

Hey team! Please add your planning poker estimate with Zenhub @dsilvam @victoralfaro-dotcms

[freddyucv]

PR: https://github.com/dotCMS/core/pull/23334 PR: https://github.com/dotCMS/core/pull/23410

[dsilvam]

Passed Internal QA: Working as expected