Improve error reporting

[0x009922]

• When you pass an invalid path param, e.g. 4123 to /blocks/{hash} (i.e. /blocks/4123), you get the following 400 error:

  $ fetch http://localhost:4000/api/v1/transactions/4123
  invalid value: string "4123", expected a 32-byte hex string
  

• Same for query params:

  $ fetch http://localhost:4000/api/v1/blocks?page=false
  Bad Request: Bad query: Query deserialize error: invalid digit found in string