Refactor naming

[Revazashvili]

1. private readonly members should start with lowercase
2. constants should start with uppercase
3. local variable naming was inconsistent
4. fixed tests where private field was retrieved, btw I don't think it's roght to do

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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[Clifftech123]

@Revazashvili Thank you for this. It will be reviewed. Thank you for contributing