perf: make some RPC fns concurrent #17961

Job	Run time
Lint Rust	17s
cargo deny	33s
Rust doc comments	20s
Check if node constants are up to date	2s
Check provider database	5s
Build C library (ubuntu-latest)	2m 28s
Python lint	13s
Build C library (macos-latest)	2m 36s
Build deltachat-rpc-server (ubuntu-latest)	2m 2s
Build deltachat-rpc-server (macos-latest)	2m 50s
Rust tests (ubuntu-latest, 1.84.0)	3m 6s
Build deltachat-rpc-server (windows-latest)	6m 56s
Rust tests (windows-latest, 1.84.0)	8m 56s
Rust tests (macos-latest, 1.84.0)	3m 38s
Rust tests (ubuntu-latest, 1.81.0)	3m 8s
CFFI Python tests (ubuntu-latest, 3.13)	6m 29s
CFFI Python tests (macos-latest, 3.13)	4m 50s
CFFI Python tests (ubuntu-latest, pypy3.10)	7m 28s
CFFI Python tests (macos-latest, pypy3.10)	5m 54s
CFFI Python tests (ubuntu-latest, 3.8)	6m 33s
JSON-RPC Python tests (ubuntu-latest, 3.13)	1m 50s
JSON-RPC Python tests (macos-latest, 3.13)	1m 56s
JSON-RPC Python tests (windows-latest, 3.13)	2m 55s
JSON-RPC Python tests (ubuntu-latest, pypy3.10)	1m 45s
JSON-RPC Python tests (macos-latest, pypy3.10)	2m 18s
JSON-RPC Python tests (ubuntu-latest, 3.8)	2m 11s
	1h 21m 19s

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