refactor: use mail-builder instead of lettre_email #18049

Job	Run time
cargo deny	29s
Check if node constants are up to date	2s
Lint Rust	2m 31s
Check provider database	8s
Rust doc comments	13s
Build C library (ubuntu-latest)	2m 33s
Python lint	12s
Build C library (macos-latest)	2m 18s
Build deltachat-rpc-server (ubuntu-latest)	2m 13s
Rust tests (ubuntu-latest, 1.84.0)	2m 58s
Build deltachat-rpc-server (macos-latest)	2m 20s
Rust tests (windows-latest, 1.84.0)	8m 24s
Build deltachat-rpc-server (windows-latest)	8m 4s
Rust tests (macos-latest, 1.84.0)	3m 22s
Rust tests (ubuntu-latest, 1.81.0)	2m 58s
CFFI Python tests (ubuntu-latest, 3.13)	4m 20s
CFFI Python tests (macos-latest, 3.13)	4m 48s
CFFI Python tests (ubuntu-latest, pypy3.10)	6m 17s
CFFI Python tests (macos-latest, pypy3.10)	6m 18s
CFFI Python tests (ubuntu-latest, 3.8)	4m 20s
JSON-RPC Python tests (ubuntu-latest, 3.13)	42s
JSON-RPC Python tests (macos-latest, 3.13)	43s
JSON-RPC Python tests (windows-latest, 3.13)	26s
JSON-RPC Python tests (ubuntu-latest, pypy3.10)	41s
JSON-RPC Python tests (macos-latest, pypy3.10)	44s
JSON-RPC Python tests (ubuntu-latest, 3.8)	41s
	1h 8m 45s

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