Update version to 2.0.0.0. Ported to .NET 5.

Ported to .NET 5.

The projects no longer rely on DLLs placed in the SharedLibraries folder and has now been updated to use NuGet packages for all external dependencies.

Modified FileSystem to include Windows specific functionality in their own classes, which are limited to being called only if run on the Windows platform. If called from other platforms they will return empty or null values.

Modified ActiveDirectory to limit access to certain methods that rely on Windows-specific functionality to being called only if run on the Windows platform. If called from other platforms they will return empty or null values.

Added property level access to FileStream. Resolves #10

Removed NoSql projects that weren't in wide use.
- Galactic.NoSql.Couchbase
- Galactic.NoSql.MongoDB

Removed SharePoint project, in prep for transition to Microsoft Graph. (It will likely be added back in a future release.)

Remove Galactic.Configuration project. This was developed prior to the broad availability to secret vaults that are commonly used today, and as such is being removed. All constructors that reference it in the codebase have likewise been removed.

Convenience methods in the Cryptography project that facilitated the creation and manipulation of consolidated strings for use primarily by the Configuration project have been removed.

Removed Galactic Calendar projects. These were not widely used.
- Galactic.Calendar
- Galactic.Calendar.iCalendar

Removed Galactic.Web.Security projects. These are not relevant to .NET 5 projects.
- Galactic.Web.Security.ActiveDirectory
- Galactic.Web.Security.SimpleActiveDirectory
- Galactic.Web.SimpleMapping

Removed DnDNS library dependency as it hasn't been ported to .NET 5. Replaced with DnsClient.NET.

Removed automatic assembly versioning logic as functionality this is now baked into .NET 5 solution files.

Updated LICENSE and README to reflect new development.