Remove Templates context and use templates query hook directly

[stalniy]

Why

Currently templates are fetched despite the fact whether they are needed or not that specific page. We want to call /templates endpoint only if they are needed

What

Remove Templates context and use templates query hook directly (or write a wrapper around it if it's required)

Acceptance

• /templates endpoint is not called if templates are not used on that page
• ensure /templates endpoint is called only once on page load and its response is reused between components