feat: config validation (#2412)

* feat: basic user config validation

* fix: simplify config resolution and fix issue #327

* fix: remove no longer needed function

* fix: disable some unwanted validations

* fix: improve config validation

* fix: remove redundant validation

* fix: use reduceRight instead of reverse

* fix: rollback some code

* fix: drop invalid type casts

* fix: rollback unnecessary changes

* fix: rollback config validation

* fix: add missing type-guards and restore order

* fix: one more order change

* fix: add one more missing type guard

* fix: remove unused types reference

* fix: add additional unit tests

* fix: add additional regression tests
- remove also unnecessary type check

* fix: remove more unnecessary code changes

* fix: correct order of merging plugins

* fix: add missing type check

* fix: remove invalid type check

* fix: remove redundant code

* feat: implement config validation

* fix: allow to use function as a rule

Author: armano2

@commitlint/cli/src/cli.ts

@@ -7,14 +7,15 @@ import resolveGlobal from 'resolve-global';
 import yargs, {Arguments} from 'yargs';
 import util from 'util';
 
-import {CliFlags, Seed} from './types';
+import {CliFlags} from './types';
 import {
 	LintOptions,
 	LintOutcome,
 	ParserOptions,
 	ParserPreset,
 	QualifiedConfig,
 	Formatter,
+	UserConfig,
 } from '@commitlint/types';
 import {CliError} from './cli-error';
 
@@ -364,7 +365,7 @@ function getEditValue(flags: CliFlags) {
 	return edit;
 }
 
-function getSeed(flags: CliFlags): Seed {
+function getSeed(flags: CliFlags): UserConfig {
 	const n = (flags.extends || []).filter(
 		(i): i is string => typeof i === 'string'
 	);

@commitlint/cli/src/types.ts

@@ -18,8 +18,3 @@ export interface CliFlags {
 	_: (string | number)[];
 	$0: string;
 }
-
-export interface Seed {
-	extends?: string[];
-	parserPreset?: string;
-}