feat: add support for optional parameters in nano contract serializer/deserializer

[pedroferreira1]

Acceptance Criteria

• Add support in the serializer and deserializer class for optional parameter.
• Fix bug in the signed data deserializer, where the bytes value was not being converted to hex.

Note: Unfortunately, we currently don't have any blueprints with optional parameters, so we can't test this in the integration tests, thus only unit tests were added.

Security Checklist

• Make sure you do not include new dependencies in the project unless strictly necessary and do not include dev-dependencies as production ones. More dependencies increase the possibility of one of them being hijacked and affecting us.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.63%. Comparing base (cef19d9) to head (fdea37f).

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #647       +/-   ##
===========================================
+ Coverage   62.01%   79.63%   +17.61%     
===========================================
  Files          77       77               
  Lines        5826     5838       +12     
  Branches     1210     1227       +17     
===========================================
+ Hits         3613     4649     +1036     
+ Misses       2116     1172      -944     
+ Partials       97       17       -80     

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[r4mmer]

Do we have a list of types or modifiers?
If so I think we should add a link to it with the see tag.

[tuliomir]

Another alternative to a @see tag, since we're using Typescript on this repository, would be to add a type for the type parameter.

It's a developer-friendly way to have this information always at hand, and static code validation, on compatible IDEs.

[pedroferreira1]

As we discussed in private, we currently don't have this documentation link. Also, the list of possible types is not static, so the documentation link is better.

I created an issue so we can track this when we have the documentation link. #649

[tuliomir]

Another alternative to a @see tag, since we're using Typescript on this repository, would be to add a type for the type parameter.

It's a developer-friendly way to have this information always at hand, and static code validation, on compatible IDEs.