Convert search and add-on detail page to sagas

[kumar303]

Instead of using async-connect to pre-load the add-on detail page, we should use a saga. As part of this, let's also stop populating the add-on detail page with data from search results because it will fix bugs like https://github.com/mozilla/addons-frontend/issues/2435

Steps to test this for QA:

• Load the add-on detail page, make sure it works.
• Try refreshing the detail page, make sure it still works.
• Try searching for an add-on and navigating to its detail page, make sure it works.

[kumar303]

This is a step towards #10365

[kumar303]

I moved this to #10479 and #10478 . I'll do the search conversion later once I catch my breath.

[vcarciu]

Verified all scenarios from description and more other around and everything looks fine.
Marking as verified.

[kumar303]

whoops, sorry. I closed this because it was invalid but I forgot to change the flags. No code change landed.

[vcarciu]

I will remove the verified label then and verify same scenarios for the other issues. Thanks