CP-10741: setup offramp withdrawal limit

[ruijialin-avalabs]

Description

Ticket: CP-10741

• rename and refactor onramp and offramp components and routes
• add offramp sell api to check sell limit (unfortunately we only get BTC and ETH min/max limit given our configured service providers. The ones that we we don't know the limit, we will get the error when we try to get the quote)
• update logic based on category to determine if the api should execute onramp or offramp transaction

Screenshots/Videos

RecordIt-1751300106.MOV

Checklist

Please check all that apply (if applicable)

• I have performed a self-review of my code
• I have verified the code works
• I have added/updated necessary unit tests
• I have updated the documentation