Daschat-base

:speech_balloon: Add or update text and literals

* Added more messages to `messages.py` and custom message factories.

:label: Add or update types

* Added `ResultFieldSchema` and `DispatchCallOutSchema` schemas. They will be used to standardize the return of API calls and modules.
* Created `messages.py` to hold all text messages generated by daschat.
* Added the `department` field to the `MessageSchema` schema. In the future it will allow to register in the log who wrote the message sent to the contact.
* Changed max size of `agent_id`, `agent_name` fields in the `MessageSchema` schema.

:label: Add or update types

* Created `version.py` for package version info.
* Created `types.py` to be the global type and class definition center.
* Added new enum type `MessageDispatchEnum` in `WebhookTypesEnumtypes.py`.
* Added the `dispatch` field to the `MessageSchema` schema. In the future it will allow to select wich module of **DasChat** will process the message.

:label: Add or update types

* Added the `agent_id`, `agent_name` fields to the `MessageSchema` schema. In the future it will allow to register in the log who wrote the message sent to the contact.
* Added new webhook type `CHAT_FORWARDED` in `WebhookTypesEnum` for when the chat is transferred to another agent or bot.

:construction: Work in progress

* Added module `dc_abc_channel.py` with abstract class `ChannelBase` for channels plugins.

:pencil2: Fix typos

* Proprerty `info` has same name as `info` method. Changed proprerty name to `info_data`.

:sparkles: New features

:boom: Breaking changes

* Added `info` method to `HandoffBase` class.