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>

substrate/client/utils/Cargo.toml

@@ -17,10 +17,10 @@ lazy_static = "1.4.0"
 log = "0.4"
 parking_lot = "0.12.1"
 prometheus = { version = "0.13.0", default-features = false }
-sp-arithmetic = { path = "../../primitives/arithmetic", default-features = false}
+sp-arithmetic = { path = "../../primitives/arithmetic", default-features = false }
 
 [features]
-default = [ "metered" ]
+default = ["metered"]
 metered = []
 
 [dev-dependencies]