Add Storage Extension Support

[microdev1]

Adds ability to extend CIRCUITPY storage by utilizing the next update partition on boards with dualbank support.

The ota_x and user_fs partitions are presented as a continuous flash storage block with user_fs always forming the first part and the second part is one of the ota_x next update partition. These partition may not be contiguous in the partition-table.

Couple limitations as re-sizing filesystem without erasing isn't supported currently:

1. Filesystem needs to be erased when re-sizing.
2. If both ota_x app partitions need to contain bootable image, storage extension has to be turned off.

Note: TinyUF2 will need to be updated so it flashes the next update partition instead of defaulting to ota_0 in order to avoid data corruption when storage is extended.

[bill88t]

Is this ready for testing?
Or do we first have to wait for tinyuf2?

[microdev1]

@bill88t You can start with testing.

[bill88t]

Manually built f44288d and flashed on waveshare_esp32s2_pico as a uf2.

Had to look in the source to find it. storage.erase_filesystem(extended=True)
This needs to be documented.

Attempting a wget test.

Works just fine.
Let's try some more stuff.

It works if we go back to the first partition and to the 2nd again.

[bill88t]

If extended is not specified it assumes True, extending the storage. I did test that.
extended=False also works as expected.

[jepler]

I appreciate you re-working how the storage.erase_filesystem call will work.
I have one minor nit, though.

[dhalbert]

I like this API -- thanks!

addressed

[dhalbert]

Just one thing!

[dhalbert]

Glad to get this in -- it will be in beta.2, which is imminent.