Addresses RAW HTML warning in reference/tools page. (#300)

* Adds Programs section and subsections. (#277)

* Add summary for Programs page. (#296)

* Adds missing dependencies for local devnet install.

* Improves devnet structure. Updates build-from-source steps.

* Adds summary intro to Programs.

* Revert "Add summary for Programs page. (#296)" (#297)

This reverts commit 095bbd1.

* Removes raw HTML comment.

* Removes content from another branch. Oops.

content/reference/tools.md

@@ -7,8 +7,6 @@ lead: "A list of useful tools, workflows, and projects that can help developers
 
 {{< image src="../images/polkadot-explorer-page.png" >}}
 
-<!--[![Screenshot of the Polkadot Chain Explorer page.](./images/polkadot-explorer-page.png)](https://polkadot.js.org)-->
-
 [polkadot.js.org/apps](https://polkadot.js.org/apps/?rpc=wss%3A%2F%2Ftestnet.entropy.xyz#/explorer)
 
 A one-size-fits-all blockchain explorer for Substrate-based chains, built by the [Polkadot.js team](https://polkadot.js.org/).