Feature: Destructured imports in variable declarations, Refactor parser with Babel type guards

[MajorLift]

Love this project, and having a ton of fun going through the code!

1) Features

• Newly supports object destructuring with alias assignment in variable declaration imports
  • e.g. const { foo1: bar1, foo2 } = import("module");
• Also adds support for array destructuring in variable declaration imports
  • e.g. const [foo, bar] = import("module");
• This needs more work:
  Adds support for subset of "export * from 'module'" syntax (Components exported with "export * from ..." are shown in error in the drawer #99), where an index.js,ts file containing such export statements can be used to import the parent folder as a module (a.k.a "barrel" files or batch exports) (Fixes Issue 85).

2) SaplingParser

• Extensive rewrites in .getImports(), .findVarDecImports() methods.
• Explicit checks with strong typing for all possible variations in import statements.
• Passes all previously written tests.
• Readability, modularity, extensibility improvements.
• WIP: Glob imports with namespace specifiers (import * as namespace from "module")

3) ComponentTree, TreeItem

• These class object implementations are tentative proposals.
• Referenced vscode-treeview's TreeDataProvider/TreeItem design pattern and API.
• Seems advisable to decouple tree state data/methods from parsing logic (MVC: Model - data objects, Controller - parser, View - webview).
• The parser could be made into a static class with only .parse() exposed as public without any loss in functionality.
• TreeItems only contain reference ids to self, children, ancestors, while nodes themselves are kept in a normalized data store in ComponentTree. Therefore currently a breaking change. Vscode messaging and webview would need to be updated as well.
• WIP: Should make implementing expandAll/collapseAll more straightforward and performant.

4) Linter config revamp

• Stronger typing and stricter checks.
• Promotes best practices.

Water for the tree :)

[MajorLift]

Closing and creating new PR to keep Issue 85 open.