[SERVICES-2427] Search by token (ID/ticker/name) for pairs and tokens queries

[mad2sm0key]

Reasoning

• allow filtering by a partial search term for tokens and pairs (to be used for quick-search capability)

Proposed Changes

• add searchToken field to PairsFilter and TokensFilter input args
• add filtering method that checks for presence of search term in the first or second tokens identifier, ticker or name (pairs filtering service)
• add filtering method that checks for presence of search term in the tokens identifier, ticker or name (tokens filtering service)

How to test

• On filteredPairs query should return all pairs where the first or second tokens identifier, ticker or name contain the string crypt:

query {
  filteredPairs(
    filters:{
      searchToken:"crypt"
    }
  ) {
    edges {
      cursor
      node {
        address
        firstToken {
          identifier
          name
          ticker
        }
        secondToken {
          identifier
          name
          ticker
        }
      }
    }
    pageInfo {
      startCursor
      endCursor
    }
    pageData {
      count
      limit
      offset
    }
  }
}

On filteredTokens query should return all tokens with the identifier, name or ticker containing the string crypt:

query {
  filteredTokens(
    filters:{
      searchToken:"crypt"
    }
  ) {
    edges {
      cursor
      node {
        identifier
        name
        ticker
        price
      }
    }
    pageInfo {
      startCursor
      endCursor
    }
    pageData {
      count
      limit
      offset
    }
  }
}