Previously we used `from jax.experimental.export import export` and
`export.export(fun)`. Now we want to add the public API directly
to `jax.experimental.export`, for the following desired usage:
```
from jax.experimental import export
exp: export.Exported = export.export(fun)
ser: bytearray = export.serialize(exp)
exp1: export.Exported = export.deserialized(ser)
export.call(exp1)
```
This change requires changing the type of
`jax.experimental.export.export` from a
module to a function. This confuses
pytype for the targets with strict type checking,
which is why I attempt to make this change
atomically throughout the internal code base.
In order to support backwards compatibility with
OSS packages, this change also includes explicit
JAX version checks in several OSS packages, and
also adds to the `export` function the attributes
that the old export module had.
PiperOrigin-RevId: 596563481
69788d18b6