Standarize decimal responses

[phoenix-web3]

• I have read the Contributing file of the documentation.
• I have searched the issues (including closed ones) and believe that this is not a duplicate.
• I am willing to lend a hand to help implement this feature.

Feature Request

Feature Description

To standardize all responses that return a decimal number it is proposed to return all such responses in JSON number type.

Due to the poor implementation of the standard number type in languages like Javascript it may cause some problems in the future to return data as Number instead of String.

Use Case(s)