[FEATURE] Make commonly flagged syntax rules enforceable by spotless

[martin-gaievski]

We can automate enforcement for some of the syntax rules by using spotless plugin. This should save time for PR reviews and improve the code in general.

For now I can see one such rule:

• negative boolean expressions should use the form foo == false instead of !foo. This is from core guidelines

[martin-gaievski]

I can think of few other rules that routinely pop up during the PR review:

• user String.format(Locale, "your message %s", param) instead of direct concat of strings "your message" + param.toString()
• set method parameters in public methods final