New daily env config

[Jasminna]

OVERVIEW

Daily environment config added. Documentation improvements for payments and subscribe methods.

WHERE SHOULD THE REVIEWER START?

index.d.ts
package.json
/src/config.ts
/src/index.ts
/src/models/CommonInterfaces.ts

ANY NEW DEPENDENCIES ADDED?

List any new dependencies added.

• Does it work in IE >= 11?
• Does it work in other browsers?

CHECKLIST

Be sure all items are ✅ before submitting a PR for review.

• Verify you bumped the lib version according to Semantic Versioning Standards
• Verify you updated the CHANGELOG
• Verify this branch is rebased with the latest master