Remove nb crate

[SergioGasquez]

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Submission Checklist 📝

• I have updated existing examples or added new ones (if applicable).
• I have used cargo xtask fmt-packages command to ensure that all changed code is formatted correctly.
• My changes were added to the CHANGELOG.md in the proper section.
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Pull Request Details 📖

Description

This PR modifies spi/uart/timer to remove some nb::Results and embedded-hal-nb stuff.

• read_byte/write_byte are now blocking for uart and spi.
  • I guess those would be removed in Remove the single byte read/write inherent functions #2808 (i noticed it too late i guess)
• In uart, read_bytes/write_bytes return how many bytes they read/wrote.

Testing

Describe how you tested your changes.

Closes #2729
Closes #2730