Add pair swap fee sort options to Advanced Search

[kenkunz]

Goal

As a user searching for trading pairs on the Advanced Search UI, I want to sort pairs based on pair swap fee (ascending or descending).

Acceptance Criteria

• New search options are displayed at the end of the current list of options:
  • ▲ Swap Fee
  • ▼ Swap Fee
• Search results should update to reflect the selected sort order
• URL params should update to reflect the selected sort option (so if the user navigates forward/back or shares search URL, the selected sort option and search results reflect the original selections)

Related

• 427

[kenkunz]

These filter options may not add much value. We already include pool_swap_fee:asc as a secondary sort criterion in all of the other sort options.