Upgrade from Angular 10 to Angular 12

Here's a branch:

https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/berick/lp1948035-angular-12

Minimal changes required. "ng update" did most of the work. Initial UI testing looks good.

Beware of a few things:

1. A couple of tests are failing for DateRangeSelect and EgHelpPopoverComponent. It was not immediately clear to me how to fix them.

2. I could have updated ng-bootstrap to version 10, however v10 no longer supports NgbTabset (which is currently deprecated), so a number of our components break. Because of this, I stuck with version 7. We should migrate all ng-bootstrap tabs to navs before the next update. (Will open a new LP).

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To update an existing server:

cd /tmp
wget 'https://nodejs.org/dist/v14.18.1/node-v14.18.1-linux-x64.tar.xz'
sudo tar -C /usr/local --strip-components 1 -xJf node-v14.18.1-linux-x64.tar.xz
sudo npm install -g @angular/cli@^12.2.0
cd $EVERGREEN/Open-ILS/src/eg2
rm -rf node_modules/
npm install
ng build # etc.

Opened separate bug for NgbTabset replacement: https://bugs.launchpad.net/evergreen/+bug/1948693

Rebased to master:

https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/berick/lp1948035-angular-12-v2

Prod/dev builds still working OK.

Note if 'npm install' takes longer than usual, there is an unresolved issue related to this. The build will eventually complete after several minutes. https://github.com/npm/cli/issues/2306

See previous comments for updating an existing server.

Works well for me, Bill! Thanks for getting us up to date. I've pushed this to master.

I also added a follow-up commit to resolve the three failing tests. Tests have their own tsconfig, which was using commonjs module definitions rather than the default esnext ones. Something seems to have come to a head in Angular 12 that makes the commonjs option no longer work -- didn't have the chance to dig around much on this. Anywho, I removed that line from the config, and now the tests are passing.

Noting a follow-up bug report related to the deprecated linter: bug 1959048