Remove the Releases docs pages and point to the GitHub releases [skip ci]

Author: elenadimitrova

docs/_Docs_Releases.md

@@ -23,4 +23,4 @@ A function signature lookup will return the address of the contracts that implem
 
 ![EtherRouter](img/delegateProxyCallchain_1.png)
 
-This pattern enables both fine-grained control of permissions for individual functions (see below), well as eternal backwards-compatibility following network upgrades. To learn more about planned upgrades to the Colony Network, please see [Releases](/colonynetwork/docs-releases/).
+This pattern enables both fine-grained control of permissions for individual functions (see below), well as eternal backwards-compatibility following network upgrades.

docs/_Docs_Upgrades.md

@@ -27,7 +27,7 @@ The Colony Network is the infrastructure upon which all colonies run.
 
 The colonyNetwork repository contains the solidity implementation of Colony, which is developed as free software. See our [guidelines](https://github.com/JoinColony/colonyNetwork/blob/develop/docs/CONTRIBUTING.md) if you're interested in contributing to the colonyNetwork codebase. Developers interested in contributing to the Colony Network are encouraged to look at the code on [GitHub](https://github.com/JoinColony/colonyNetwork), and to come say hi on [Gitter](https://gitter.im/JoinColony/colonyNetwork).
 
-The current colonyNetwork release is [glider](/colonynetwork/docs-releases). Glider implements some, but not all, of the Colony Protocol:
+The current colonyNetwork release is [glider](https://github.com/JoinColony/colonyNetwork/releases). Glider implements some, but not all, of the Colony Protocol:
 
 * Ownership and permissions (through roles)
 * Reputation