improve the implementation of API: /api/v1/addresses/:id

[iamyates]

Currently this api does not always return expected result . ( refer to issue: )
The root cause is that:

1. in database , the decimal data stored in both udts and udt_accounts tables. however, the udt_accounts table not always has decimal data ( default is null )
2. in API, the decimal data currently comes from udt_accounts tables

solution: should improve the point 2 above, make the decimal data comes from udts table.