Use embedded-storage traits

[Oakchris1955]

Since this library is mainly targeted for embedded devices, perhaps we could use embedded-storage's traits instead of our own, instantly adding support for most flash devices.

[Oakchris1955]

@alexkazik since you are the one that created the BlockTranslator struct, what do you think?

[alexkazik]

I'd vote against replacing it, because the BlockTranslator does buffer N pages, and only writes when flushing or needing a new buffer.
On the other hand if writing two e.g. 512 byte blocks with embedded-storage's Storage trait, the larger flash-block will be read, modified, erased and written for each of those two writes, making it way slower and also increases the number of erases (which are limited on nor flash).

However using the trait NorFlash as the base of BlockTranslator is worth in investigation (maybe rename it then even).
Though maybe embedded-storage is not yet finished enough, seeing that the offset is sometimes u32 (read/write) and sometimes usize (read capacity).
The u32 limit will also not allow for >=4GiB flashs, though Nor Flash is not that big to begin with.
Should I try and tinker a bit around?

(And I don't think that BlockBase/Read and so on should be replaced by NorFlash because it's to specific.)

[Oakchris1955]

The NorFlash and ReadNorFlash read, write and erase offsets are a u32, which means that no Flash storage device with more than 4GiB would work (and judging by embedded-storage's reverse dependencies, that seems to be their target. I could write a basic wrapper between their NorFlash and ReadNorFlash traits and our own block traits, but that would probably also be easy for someone to implement themselves.

[alexkazik]

The Read/NorFlash offset is in bytes, and this limits the device to 4 GiB, which is more than big enough for NorFlash.

Should I create a PR for the stuff I made (above)?

[Oakchris1955]

No, I will make a translator between their NorFlash traits and our Block traits when I have the time.

[alexkazik]

Ok, but feel free to pick from it what helps you. (It does work.)

[Oakchris1955]

Implemented translators for ReadNorFlash and NorFlash traits with #36