Rough implementation of DBAPI & sqlalchemy dialect

[charlesbluca]

Definitely needs some work, but at the moment this enables us to query tables in a pre-populated dask_sql.Context through sqlalchemy with something like:

import dask.config

from dask_sql import Context
from dask.datasets import timeseries

from sqlalchemy import text

dask.config.set({"dataframe.convert-string": False})

c = Context()

c.create_table("df", timeseries())

with c.sqlalchemy_connection() as conn:
   result = conn.execute(text("select * from df where name = 'Alice'")).fetchall()

cc @randerzander @jdye64

[codecov-commenter]

Codecov Report

Attention: 160 lines in your changes are missing coverage. Please review.

Comparison is base (c274609) 83.12% compared to head (fb6e77d) 82.45%.

Files	Patch %	Lines
dask_sql/integrations/dbapi.py	0.00%	138 Missing :warning:
dask_sql/integrations/sqlalchemy.py	0.00%	17 Missing :warning:
dask_sql/context.py	16.66%	5 Missing :warning:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1303 +/- ## ========================================== - Coverage 83.12% 82.45% -0.68% ========================================== Files 77 79 +2 Lines 4261 4422 +161 Branches 795 814 +19 ========================================== + Hits 3542 3646 +104 - Misses 550 607 +57 Partials 169 169 ```

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