Expose pypika query building

Is your feature request related to a problem? Please describe. Tortoise is great, but it lacks some features like jsonb filtering.

Describe the solution you’d like Expose internal make_query, so one can create queryset using existing Tortoise API and update it with more complex logic using query builder. For example

qs = Model.filter(...).limit(100)
raw_query = qs.query  # in current implementation qs.query is empty
raw_query.select().where()

For now one should use

qs = Model.filter(...).limit(100)
qs._make_query()  # make query using pypika as query builder
raw_query = qs.query

[long2ice]

Now you can use queryset.as_query()

[AlwxSin]

For now, I have to use this snippet

import typing as tp
from copy import copy

from pypika import Criterion
from tortoise import QuerySet, Model


class CriterionQuerySet(QuerySet):
    __slots__ = QuerySet.__slots__ + ("_additional_and_criterions",)

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._additional_and_criterions: tp.List[Criterion] = []

    @classmethod
    def from_model(cls, model: tp.Type[Model]) -> "CriterionQuerySet":
        """"""
        return cls(model)

    def add_and_criterion(self, criterion: Criterion) -> None:
        self._additional_and_criterions.append(criterion)

    def _clone(self):
        """We need to copy all method because Tortoise use Specific class"""
        # here can be queryset = self.__class__.__new__(self.__class__)
        queryset = CriterionQuerySet.__new__(CriterionQuerySet)
        queryset.fields = self.fields
        queryset.model = self.model
        queryset.query = self.query
        queryset.capabilities = self.capabilities
        queryset._prefetch_map = copy(self._prefetch_map)
        queryset._prefetch_queries = copy(self._prefetch_queries)
        queryset._single = self._single
        queryset._raise_does_not_exist = self._raise_does_not_exist
        queryset._db = self._db
        queryset._limit = self._limit
        queryset._offset = self._offset
        queryset._fields_for_select = self._fields_for_select
        queryset._filter_kwargs = copy(self._filter_kwargs)
        queryset._orderings = copy(self._orderings)
        queryset._joined_tables = copy(self._joined_tables)
        queryset._q_objects = copy(self._q_objects)
        queryset._distinct = self._distinct
        queryset._annotations = copy(self._annotations)
        queryset._having = copy(self._having)
        queryset._custom_filters = copy(self._custom_filters)
        queryset._group_bys = copy(self._group_bys)
        queryset._additional_and_criterions = self._additional_and_criterions
        return queryset

    def _make_query(self) -> None:
        super()._make_query()
        for criterion in self._additional_and_criterions:
            self.query._wheres &= criterion