This commit updates the docs examples to be compatible with the
`prefer-const` tslint rule.
This is in preparation of updating the docs examples `tslint.json` to
match the one generated for new Angular CLI apps in a future commit.
PR Close#38143
This commit was worked on by a number of people including
@filipesilva, @gkalpak and @wardbell. It contains changes that:
* remove unused files,
* fix the bootstrap approach to ensure that bootstrap is in the correct Zone
* fix unclosed code-example tags
* replace use of "we" with "you"
* remove broken dual router example
Related to angular/angular.io#3541
