Use limits directly instead of Flask-Limiter

[psrok1]

Your checklist for this pull request

• I've read the contributing guideline.
• I've tested my changes by building and running the project, and testing changed functionality (if applicable)
• I've added automated tests for my change (if applicable, optional)
• I've updated documentation to reflect my change (if applicable)

What is the current behaviour?

I tried to modify something around limits and feel that Flask-Limiter is not exactly a good fit to our needs. rate_limited_resource decorator is awfully hacky and Flask-Limiter doesn't provide a good way to make more dynamic configuration of limits.

What is the new behaviour?

In the same time: Flask-Limiter is just a wrapper on limits library. I found we can use it directly and implement rate limiting in before_request instead of relying on decorators

Test plan

1. Enabled rate limits and set pretty low limit for method and resource
2. Hit the limit and checked if Rate-Limit header looks good