4.5 release notes update 1 (#256)

* add contributors and warning rainbow at32

* add HD OSD colour support, remove spaces

* update rpm limiter info

* Pre-arm race settings OSD build option added

* include within blackbox mapping from bonchan

* add link to all PRs tagged 4.5 milestone

* review comments addressed, TBS binding added

* Update docs/release/Betaflight-4.5-Release-Notes.md

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Co-authored-by: Mark Haslinghuis <[email protected]>