Enforce consistent and correct toml formatting (#2518)

Using taplo, fixes all our broken and inconsistent toml formatting and
adds CI to keep them tidy.

If people want we can customise the format rules as described here
https://taplo.tamasfe.dev/configuration/formatter-options.html

@ggwpez, I suggest zepter is used only for checking features are
propagated, and leave formatting for taplo to avoid duplicate work and
conflicts.

TODO
- [x] Use `exclude = [...]` syntax in taplo file to ignore zombienet
tests instead of deleting the dir

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Bastian Köcher <git@kchr.de>

polkadot/node/network/approval-distribution/Cargo.toml

@@ -31,7 +31,8 @@ polkadot-primitives-test-helpers = { path = "../../../primitives/test-helpers" }
 
 assert_matches = "1.4.0"
 schnorrkel = { version = "0.9.1", default-features = false }
-rand_core = "0.5.1" # should match schnorrkel
+# rand_core should match schnorrkel
+rand_core = "0.5.1"
 rand_chacha = "0.3.1"
 env_logger = "0.9.0"
 log = "0.4.17"