Update to the latest version of Angular

[AndreyBespamyatnov]

It is 11th version already, and we can get some performance improvements just for free

[berezovskyi]

To be a bit conservative, I made an update from 9 to 10.2 last year: 73701ef

The list for 10.2 -> 15 is quite long: https://update.angular.io/?v=10.2-15.0

[AndreyBespamyatnov]

@berezovskyi just as advice, it is always better to do one version upgrade, 9 to 10, then to 11, then to 12 and so on

[Jad-el-khoury]

Good you're keeping an eye on us @AndreyBespamyatnov ! hope you are doing well otherwise.

[AndreyBespamyatnov]

@Jad-elkhouy I'm good, thanks, I always look into that and am ready to help)

[berezovskyi]

So I tried doing a 10->11 upgrade yesterday and succeeded only partly (#117 and oslc-op/refimpl#344). Ended up rewriting the selection dialog to use HTMX and PicoCSS instead of Angular and Boostrap (see oslc-op/refimpl#345, has a short video demo). I think we should make the default Lyo approach.

Also, I am not sure why this repo exists - I think we should move the UI part into Lyo Designer and the POJO part should move into Lyo.