feat: MMPD-1522 add fetch trending token data

[Bigshmow]

Explanation

We are adding a new TokenDiscoveryApiService to handle discovery related requests.
In this PR we are introducing the first method getTrendingTokens which requests trending tokens by chain from the Portfolio API, recently introduced in this PR.

References

For reference this is the jira ticket: MMPD-1522
Related to PR-76 in Portfolio-API

Changelog

@metamask/token-search-discovery-controller

• Added:
• Introduce TokenDiscoveryApiService to keep discovery and search responsibilities separate
  • This service is responsible for fetching discover related data
  • Add getTrendingTokens method to fetch trending tokens by chain
  • Add TokenTrendingResponseItem type for trending token responses
• Export TokenSearchResponseItem type from the package index

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've highlighted breaking changes using the "BREAKING" category above as appropriate
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes