[FEATURE] V1 - Type coercions feature

[george-zubrienko]

Description

In v0 this PR aligned lib behaviour with marshmellow, but effectively triggered a couple of unexpected consequences:

• People using from_json will start noticing builtin types being implicitly converted when reading json files into dataclasses, and especially booleans receiving valid values from not-very-common-sense values like integers outside 0-1 range and strings
• People using from_dict will have even "better" experience when types in their dicts are being overridden by dataclass field type, with implicit conversion as a side-effect
• People using marshmellow interop would rejoice

Possible solution

First of all, we should add a flag for implicit coercions:

[tool.dataclasses_json]
coerce_builtins = True

Second, we should do a follow-up discussion re coercion behaviours in from_dict, IMO this should differ from from_json behaviour because from_dict argument carries type information, while from_json has to work with a string.

Alternatives

N/A

Context

Problem discovered in #466