[MOB-865] Promotions screen improvements

[JDSM01]

What does this PR do?

Adds the improvements specified in the ticket comment Also changed some logic related with unknown promotions Fixed issue with max level users Adds language support for user_stats endpoint

Database changed?

No

Where should the reviewer start?

• [ ] Foo.java
• [ ] Foo.kt

How should this be manually tested?

Test if the changes are working

What are the relevant tickets?

https://aptoide.atlassian.net/browse/MOB-865

Questions:

Does this add new dependencies which need to be added? (Eg. new libs, new keys, etc.)

Code Review Checklist

• [ ] Architecture
• [ ] Documentation on public interfaces
• [ ] Database changed?
• [ ] If yes - Database migration?
• [ ] Remove comments & unused code & forgotten testing Logs
• [ ] Codestyle
• [ ] Functional QA tests pass