ZRAM Optimizations for Odroid XU4/HC1/HC2

[ChiefGyk3D]

Made tweaks and tested them with Monero being built. Peaked at 1.85GB RAM used of 2GB with 120MB in swap but system was responsive and Monero compilation in 3 hours from forced update. CPU Seemed to be only maxing one core at a time may look into seeing if we can speed build time up just a bit more in other ways see Issue #16 for discussion and reasoning

[ChiefGyk3D]

Tested and confirmed to work on Odroid XU4 platforms wonderfully and still going

[shermand100]

Ok, let's get this included. I like the idea.

Because it's tested on the Odroid XU4/HC1/HC2 can you add in another whiptail dialog box that gives the user a choice. Something like:

"Memory optimisations are available for Odroid systems, would you like to apply them" Yes/No

YES:
echo "vm.vfs_cache_pressure=500" | sudo tee -a /etc/sysctl.conf
echo "vm.dirty_background_ratio=1" | sudo tee -a /etc/sysctl.conf
echo "vm.dirty_ratio=50" | sudo tee -a /etc/sysctl.conf
sudo sysctl -p

NO:
sudo sysctl vm.swappiness=10

Bump 24/01/22 @ChiefGyk3D