Migrate from aioredis to redis-py with asyncio support

[moznuy]

The need of migration was expressed in #16
I don't know if I've missed anything important(tests pass).
There is also

redis-om-python/aredis_om/model/model.py

Line 1483 in 8a3f0d8

await db.execute_command("JSON.SET", self.key(), ".", self.json())

and similar

redis-om-python/aredis_om/model/model.py

Line 715 in 8a3f0d8

args = ["ft.search", self.model.Meta.index_name, self.query, *self.pagination]

that could use direct api now, that is supported in redis.asyncio, I think, like:

import asyncio
import redis.asyncio as redis

async def main():
    print(await redis.StrictRedis().json().get("a"))

asyncio.run(main())

But that could be done in separate PR

[moznuy]

Any input will be appreciated

[codecov-commenter]

Codecov Report

Merging #233 (a80e37f) into main (e2ff503) will increase coverage by 0.21%.
The diff coverage is 83.33%.

@@            Coverage Diff             @@
##             main     #233      +/-   ##
==========================================
+ Coverage   77.25%   77.46%   +0.21%     
==========================================
  Files          12       12              
  Lines        1165     1154      -11     
==========================================
- Hits          900      894       -6     
+ Misses        265      260       -5     

Flag	Coverage Δ
unit	77.46% <83.33%> (+0.21%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
aredis_om/connections.py	70.00% <75.00%> (ø)
aredis_om/model/migrations/migrator.py	75.86% <75.00%> (ø)
aredis_om/_util.py	77.77% <77.77%> (ø)
aredis_om/__init__.py	100.00% <100.00%> (ø)
aredis_om/model/model.py	86.25% <100.00%> (-0.02%)	⬇️

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[dvora-h]

@moznuy Sorry that your PR waited so long but it's great and still relevant so I'm merging it now