boards: lilygo: t_oi_plus: initial support

[aisuneko]

This PR proposes initial support for the Lilygo TTGO T-OI-PLUS ESP32-C3 board, which is largely identical devicetree-wise to the TTGO T8-C3.

[github-actions]

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[kartben]

Thanks for the PR! Some initial feedback after a quick look

[aisuneko]

@kartben Thanks! I've fixed the two issues above.