Fix: fix bug in search functionality

[jkarenzi]

What does this PR do?

• This PR implements a fix for search and filter endpoints

Description of the task to be completed?

• [x] Fix search functionality such that a buyer can search by keyword, price range, category, rating or sort order
• [x] Update swagger documentation
• [x] Add pagination

How can this be manually tested?

• By making requests to the api/v1/buyer/search endpoint with different search criteria

What are the relevant pivotal trackers/story id?

• 148

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 63.63636% with 4 lines in your changes missing coverage. Please review.

Project coverage is 86.39%. Comparing base (77b44b8) to head (085e703).

Files	Patch %	Lines
src/controller/searchProducts.ts	63.63%	2 Missing and 2 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #149 +/- ## =========================================== - Coverage 86.49% 86.39% -0.10% =========================================== Files 65 65 Lines 1755 1757 +2 Branches 191 193 +2 =========================================== Hits 1518 1518 Misses 212 212 - Partials 25 27 +2 ```

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