Add TelegramId & Email fields, refactor similar methods

Предложения
1

  1. Add TelegramId, Email fields in database schema

  2. TelegramId, email – new fields available for create and update user methods.

  3. New API endpoints available.
    Be careful, this two endpoints will return array of users, cause TelegramId and Email is not unique fields.

    1. GET /api/users/tg/{telegramId}

    2. GET /api/users/email/{email}

  4. Refactor and simplify other “Get by” methods.

2

Done.