chore(sdk): add eslint

[markin-io]

Issue being fixed or feature implemented

Adds eslint

What was done?

• Added eslint package for typescript with airbnb config, handled JS files as well
• Changed certain from errors into warnings in order to not drown in long refactoring which could possibly break some code (check warnRules in .eslintrc.js)
• Manually fixed eslint errors that do not alter logical constructions (missing vars, long lines, rearranging imports and etc)
• eslint-ignored errors that require changes in logical constructions and could possibly cause bugs

How Has This Been Tested?

• CI

Breaking Changes

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone