Hash calculation by url

This introduces hash calculation for Url from the commandline, usage:

michaelchecksum https://a.com/b.zip

Preferred way for upgrading:

dotnet tool update michaelchecksum.console -g

0.0.0.3: Downgraded console to .Net Core 3.0

First release with downloadable binaries. Although the preferred way is using:

dotnet tool install michaelchecksum.console -g

When you do not have .Net Core 3 runtime installed, you can still use these binary version on Linux, Windows or OSX.

NOTE: Tested, does not work on my Linux machine without .Net Core. I will have to figure out what is going on.