Support for different blob types in mysql
Just subclass and specify the data-storage class:

```python
class LongBlogField(BlobField):
    field_type = 'LONGBLOB'
``` This is not compatible with using a proxy that can either be a sqlite or mysql, as sqlite has no longblob type, or am I mistaken? https://www.sqlite.org/datatype3.html

From 3.1.3:

> If the declared type for a column contains the string "BLOB" or if no type is specified then the column has affinity BLOB.
I would need to store some binary data larger then 65kb in a mysql database.

peewee only seems to support one `BlobField`, which maps to mysqls `blob` which is max 65kb.

How can I make sure, the table is created with a `MEDBLOB` or `LONGBLOB` datatype while also maintaining sqlite compatiblity for local testing?