Find pipe uses in inputs to structural directives

[P4]

After finally upgrading from 3.0.5 to a recent version we've noticed the pipe parser no longer detects usages like this:

<ng-container *ngTemplateOutlet="section; context: {
  title: 'example.translation.key' | translate
}"></ng-container>

Turns out it's because inputs to structural directives were not being searched at all.

This PR adds handling of templateAttrs on Template nodes that works identically to inputs.

[ismailcherri]

@biesbjerg Hi, are you free to review this? We are also facing the same problem. Thanks in advance.

[P4]

@ismailcherri I've re-made the pull request under a different fork mentioned in https://github.com/biesbjerg/ngx-translate-extract/issues/246#issuecomment-1353101571