Don’t show the side nav in mobile (not side-by-side) view when arriving or navigating.
Only show it by request.
The side nav should continue to appear in wide mode (side-by-side) when navigating from a marketing page to a guide page.
* Ensure that all indexed documents are displayed in the search results.
(Previously the guide documents were not appearing because we only showed
results that had a `name` property, rather than a `name` or `title`.)
* Group the results by their containing folder (e.g. api, guide, tutorial, etc).
* Hide the results when the user hits the ESC key.
* Hide the results when the user clicks on a search result
Closes#14852
All the docs related files (docs-app, doc-gen, content, etc)
are now to be found inside the `/aio` folder.
The related gulp tasks have been moved from the top level
gulp file to a new one inside the `/aio` folder.
The structure of the `/aio` folder now looks like:
```
/aio/
build/ # gulp tasks
content/ #MARKDOWN FILES for devguides, cheatsheet, etc
devguides/
cheatsheets/
transforms/ #dgeni packages, templates, etc
src/
app/
assets/
content/ #HTML + JSON build artifacts produced by dgeni from /aio/content.
#This dir is .gitignored-ed
e2e/ #protractor tests for the doc viewer app
node_modules/ #dependencies for both the doc viewer builds and the dgeni stuff
#This dir is .gitignored-ed
gulpfile.js #Tasks for generating docs and building & deploying the doc viewer
```
Closes#14361
