Limit fungible token decimals to 18

[tinker-michaelj]

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👾 Description of the issue

A fungible token type can set its decimals field to any integer in the range [0, 2^31).

But it is very unlikely any use case exists for values in the range [19, 2^31), since floor(log10(2^63-1)) = 18---that is, even with the maximum supply of 2^63 - 1, the entire supply of a such a token isn't even 1 whole token!

Proposed Solution:

Limit the decimals field for fungible tokens to the range [0, 18]. The decimal of a TokenCreate-transaction is checked in TokenCreateValidator.validateTokenType()

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[wenayy]

can you tell me where do i need to apply this i understand the issue but not how and where in the repo i need to use it

[wenayy]

can you assign me this issue

[b-l-u-e]

Please assign me to this issue

[hendrikebbers]

@wenayy are you still interested in working on the issue?