AA-13801 Create no-declare rule to prevent using declare keyword

.gitignore

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+coverage
+dist
+node_modules

README.md

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+# Liniting rules plugin for TypeScript ESLint by LiveChat
+
+A package of linting rules used in TypeScript ESLint.
+
+## Quick-start
+
+
+### Installation
+
+```bash
+$ npm i --save-dev @livechat/eslint-plugin
+```
+
+
+### Usage example
+
+```json
+{
+  "plugins": ["@livechat"],
+  "rules": {
+    "@livechat/no-declare": "error"
+  }
+}
+```
+
+
+## Linting rules list
+
+| Name                                                           | Description                                   |
+| -------------------------------------------------------------- | --------------------------------------------- |
+| [`@livechat/no-declare`](#no-declare)                          | Forbids using 'declare' keyword               |
+
+
+## no-declare
+
+Using 'declare' keyword may be forbidden for all or selected identifiers. You can use it for example to force another methods of declaring global variables, e.g. using 'import' forms.
+
+
+### Options
+
+```ts
+type Options = {
+  onlyIdentifiers?: string[];
+  excludeIdentifiers?: string[];
+};
+
+const defaultOptions: Options = {
+  onlyIdentifiers: [];
+  excludeIdentifiers: [];
+};
+```
+
+The rule accepts options with the following properties:
+
+- `onlyIdentifiers` (optional) - If used, only the provided identifiers will be reported. All other identifiers declared with `declare` keyword will be ignored.
+- `excludeIdentifiers` (optional) - If used, all identifiers will be reported except those provided in the array. If `onlyIdentifiers` is used, this option is ignored.
+
+
+### default options
+
+Don't use 'declare' keyword.
+
+<!--tabs-->
+
+#### ❌ Incorrect
+
+```ts
+declare const someConst: any;
+declare const window: { location };
+declare const x, y, z: number;
+```
+
+#### ✅ Correct
+
+```ts
+import someConst from 'some-lib';
+import { window } from 'utils/global-declarations';
+const { x, y, z } = window;
+```
+
+
+### onlyIdentifiers
+
+Don't use 'declare' keyword for the provided identifiers.
+
+```json
+{
+  "@livechat/no-declare": [ "error", { "onlyIdentifiers": [ "window" ] } ]
+}
+```
+
+<!--tabs-->
+
+#### ❌ Incorrect
+
+```ts
+declare const window: any;
+declare const window: { location };
+```
+
+#### ✅ Correct
+
+```ts
+import { window } from 'utils/global-declarations';
+declare const someConst: any;
+declare const x, y, z: number;
+```
+
+
+### excludeIdentifiers
+
+Don't use 'declare' keyword except for the provided identifiers. If `onlyIdentifiers` is used, this option is ignored.
+
+```json
+{
+  "@livechat/no-declare": [ "error", { "excludeIdentifiers": [ "someConst" ] } ]
+}
+```
+
+<!--tabs-->
+
+#### ❌ Incorrect
+
+```ts
+declare const window: any;
+declare const x, y, z: number;
+```
+
+#### ✅ Correct
+
+```ts
+import { window } from 'utils/global-declarations';
+declare const someConst: any;
+```

jest.config.js

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+module.exports = {
+  testEnvironment: 'node',
+  transform: { '^.+\\.tsx?$': 'ts-jest' }
+};