STM32: Fix I2C repeated start by converting to IT mode

[hierophect]

The existing implementation of I2C does not currently recognize requests for a repeated start condition, which caused reads to fail on some chips. Since only the "IT" interrupt-driven versions of the ST HAL support this feature, fixing this issue also required implementing the usual infrastructure for ST interrupts, matching other modules like UART and PulseIn.

@tannewt I didn't really touch the base implementation here, but if you think we'd benefit from moving regular I2C operations to the interrupt mode (non-blocking) I can add in the requisite timeouts/keyboard interrupt stuff.

Resolves #3736

[dhalbert]

The single build failure is the stm/boards/espruino_pico ja build, which is overflowing by over 2k bytes, which is odd, because I would have expected previous PR's to cause this.

[jepler]

If you gotta, you gotta. No testing performed. I initially wondered if i2c_assign_irq needed a "free irq" counterpart, but now I see it's just determining the preassigned IRQ for the peripheral... I'll stick on an Approve but I don't know what's going on with that failed build .. doesn't make much sense

[tannewt]

I'm fine with whatever you want to do. Please stick to one reviewer. You need to sort out the build issue before we can merge.

[hierophect]

@tannewt I added @siddacious since it was originally his issue, and he might have wanted to test.

[hierophect]

@jepler quick ping for your review again, this should be good to go.

[jepler]

change to save storage seems fine to me. though, rgbmatrix and sharpdisplay both become less useful without framebufferio so consider disabling them as well in a future commit.

[dhalbert]

We can find something else to remove instead. We were not able to understand why the ja build suddenly seemed so much larger.

[hierophect]

@jepler @dhalbert I really wouldn't worry about it - the STM32F401xD line are very tiny chips that we only see used on the Espruino Pico. It'd be a poor pick for any form of display work anyway.