Update installmonium.sh 2.1

Update banner on the script

Update installmonium.sh to 2.0 version

Update to a new version, added a new way of getting the constants installations trough releases and clean up a bit of the script

Repair Credmaster not showing as installed

Update README.md

Update README.md

Added some packages

Packages added : 
- Kerbrute
- Credmaster
- Nessus

Create installmonium.sh