Add support for configuring custom checks from a TOML file

Resolves #37 (closed)

First jab at #31 (closed)

Added features/changes

• Command to generate a TOML config file to write custom checks for values such as expected number of CDPs in data.
• Command to do validation based on a path to a TOML config file for custom checks
• Default verbosity changed from warning to info

Implementation details

• trigger_stats.rs where stats about the trigger type is collected
• custom_checks.rs where the TOML config is defined along with which kind of custom checks are available

Fix

• Git depth too shallow suddenly for checking tags in CI, adjusted that depth for the specific job that checks version number in Cargo.toml matches lates tag