Remove old website for grin.mw (#3195)

* Remove old website for grin.mw

* Also update forum

CONTRIBUTING.md

@@ -34,7 +34,7 @@ In case of problems with trying out grin, before starting to contribute, there's
 * And [see the developers chat](https://gitter.im/grin_community/dev) if you have questions about source code files.
   If you explain what you're looking at and what you want to do, we'll try to help you along the way.
 * Also see `docs/*.md` and the folder structure explanations, and [the wiki](https://github.com/mimblewimble/docs/wiki).
-* Further information and discussions are in the [Forum](https://www.grin-forum.org/), the [website](https://grin-tech.org), the [mailing list](https://lists.launchpad.net/mimblewimble/) and news channels like the [@grincouncil](https://twitter.com/grincouncil) and a (mostly unfiltered!) Twitter bot that collects headlines, mailing list posts, and reddit posts related to Mimblewimble/Grin: [@grinmw](https://twitter.com/grinmw)
+* Further information and discussions are in the [Forum](https://forum.grin.mw), the [website](https://grin.mw), the [mailing list](https://lists.launchpad.net/mimblewimble/) and news channels like the [@grincouncil](https://twitter.com/grincouncil) and a (mostly unfiltered!) Twitter bot that collects headlines, mailing list posts, and reddit posts related to Mimblewimble/Grin: [@grinmw](https://twitter.com/grinmw)
 
 ## Testing
 

SECURITY.md

@@ -77,7 +77,7 @@ page linked from our website, with a links of their choosing.
 
 There is not currently a formal bug bounty program for Grin as it would require
 a high level of resources and engagement to operate in good faith. More
-[funding](https://grin-tech.org/funding) can help provide the necessary
+[funding](https://grin.mw/fund) can help provide the necessary
 resources to run one in the future for the Grin community.
 
 ## Deviations from the Standard

core/src/pow/cuckarood.rs

@@ -17,7 +17,7 @@
 //!
 //! Cuckarood is a variation of Cuckaroo that's tweaked at the first HardFork
 //! to maintain ASIC-Resistance, as introduced in
-//! https://www.grin-forum.org/t/mid-july-pow-hardfork-cuckaroo29-cuckarood29
+//! https://forum.grin.mw/t/mid-july-pow-hardfork-cuckaroo29-cuckarood29
 //! It uses a tweaked siphash round in which the rotation by 21 is replaced by
 //! a rotation by 25, halves the number of graph nodes in each partition,
 //! and requires cycles to alternate between even- and odd-indexed edges.

core/src/pow/cuckaroom.rs

@@ -16,8 +16,7 @@
 //! John Tromp. Ported to Rust from https://github.com/tromp/cuckoo.
 //!
 //! Cuckaroom is a variation of Cuckaroo that's tweaked at the second HardFork
-//! to maintain ASIC-Resistance, as introduced in
-//! https://www.grin-forum.org/t/mid-december-pow-hardfork-cuckarood29-cuckaroom29
+//! to maintain ASIC-Resistance.
 //! It uses a tweaked edge block generation where states are xored with all later
 //! states, reverts to standard siphash, and most importantly, identifies cycles
 //! in a mono-partite graph, from which it derives the letter 'm'.