Add I2C support to STM32 platform

[pguyot]

Continuation of:

• Use official STM32 SDK for stm32 builds instead of libopencm3 #2118
• Extract from eavmlib platform-specific modules #2111
• Add I2C support to RP2 platform #2112

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

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