docs: move quick starts

move quicks starts from deep nesting to main navigation below Home
update reference throughout documentation to absolute URLs

Author: TC-MO

sources/platform/actors/development/index.md

@@ -12,7 +12,7 @@ slug: /actors/development
 
 This section will guide you through the whole story of [Actor](../index.mdx) development.
 
-You can follow chapters sequentially from [Quick start](./quick_start/index.mdx), where you learn how to create your first Actor in just a few minutes, through the more technical sections describing the whole Actor model, up to the [Performance](/sources/platform/actors/development/performance.md) section, where you learn how to fine-tune your Actor to get the most out of the Apify platform.
+You can follow chapters sequentially from [Quick start](/platform/actors/development/quick-start), where you learn how to create your first Actor in just a few minutes, through the more technical sections describing the whole Actor model, up to the [Performance](/sources/platform/actors/development/performance.md) section, where you learn how to fine-tune your Actor to get the most out of the Apify platform.
 
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