ESLint support

[DenysVuika]

Please check if the PR fulfills these requirements

[x] The commit message follows our [guidelines](https://github.com/Alfresco/alfresco-js-api/wiki/Commit-format)
[ ] Tests for the changes have been added (for bug fixes / features)
[ ] Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x")

[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] Documentation
[ ] Other... Please describe:

What is the current behavior? (You can also link to an open issue here)

What is the new behavior?

• integrate ESLint (works great with VS Code extension: https://marketplace.visualstudio.com/items?itemName=dbaeumer.vscode-eslint)
• temporarily turn some errors into the warnings (to avoid huge PR)

the npm run lint command it going to produce a lot of warnings:

5732 problems (0 errors, 5732 warnings)

that is intentional and we should address clean code in future updates, the following rules will need to be removed and code fixed:

        'prefer-const': 1,
        'no-useless-escape': 1,
        'prefer-rest-params': 1,
        'prefer-spread': 1,
        'no-prototype-builtins': 1,
        '@typescript-eslint/explicit-module-boundary-types': 1,
        '@typescript-eslint/ban-ts-comment': 1,
        '@typescript-eslint/ban-types': 1,
        '@typescript-eslint/no-var-requires': 1,
        '@typescript-eslint/no-explicit-any': 1,
        '@typescript-eslint/no-empty-function': 1,
        '@typescript-eslint/no-namespace': 1,
        '@typescript-eslint/no-inferrable-types': 1,
        '@typescript-eslint/no-unused-vars': 1

Does this PR introduce a breaking change? (check one with "x")

[ ] Yes
[x] No

If this PR contains a breaking change, please describe the impact and migration path for existing applications: ...

Other information: