Drop IE support and upgrade to Angular 13

[wkurniawan07]

Prelude: IE is reaching end-of-life on 15 June 2022, and we do not have any strong reason to support it beyond the said date.

This allows us to upgrade to Angular 13; in fact, IE is the sole reason why the recent upgrade stopped at 12, even when 13 is already stable.

• Drop IE support entirely
• Better support for Node.js 16
• Transitive dependency updates such as RxJS 7, TypeScript 4.6, webpack-dev-server 4, and ESLint 8, many of whom are causing noises in npm audit and dependabot alerts.

Side note:

• We can also take this time to bump the Node.js version requirement to 14+, since Node.js 12 is reaching end-of-life on 30 April 2022.
• Once IE11 support is dropped we can also consider upgrading to Bootstrap 5, if we find it beneficial

To-do:

• Show a warning that IE support for TM will be dropped by end of Jun 2022.
• Upgrade to Angular 13.

[SachinVel]

The current node LTS version 16.16.0 is not compatible with angular 12.2.6 version as well. So it's better to upgrade to angular 13 version as soon as possible.