Feat(primitive): moved some alloc:string to arrayvec::arrayString

[SWASTIC-7]

implementing #999

Motivation

The issue was to move String from alloc::string::String to arrayvec::arrayString

Solution

Changed String to fixed capacity stack based String pub type String = ArrayString<80>;

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[DaniPopes]

this is not correct, Signed is fixed size but not to 80. also this is not what the issue is requesting, we would want to add a "alloc" feature and move users under that feature instead of using array strings.