Proji now uses gorm to power its main storage. Gorm simplifies proji's
code base vastly and allows usage of mysql, mssql, postgres and sqlite
databases as backend storage. Updates to the main config will follow
soon. Notice that the models which represent tables in the database also
changed and are not backwards compatible and definitly breaking.

Removed most of the tests after refactoring the storage package and will
do pretty much all tests of the repo in the very near future.

The makefile was adapted from
https://github.com/goreleaser/goreleaser/blob/master/Makefile and allows
you to setup the environment, build, format, lint and test the project
and list todo items from the code.

UnsupportedDatabaseDialectError decribes an error in the case that a
driver to a unsupported database dialect got passed.

See
https://gorm.io/docs/connecting_to_the_database.html#Supported-Databases
for a list of supported drivers.

In case of an unsupported database driver, the function will now return
a UnsupportedDatabaseDialectError. Previously the default case just set
the dialector to nil and returned an empty error.

The const TokenKeys in the code don't actually hold the token but the
config key under which the token may be found and included.

The main config now allows the specification of a custom database. You
can set the database.driver and database.dsn fields. Check the docs for
more informations. Defaults to 'sqlite3' as a driver and 'db/proji.sqlite3' as a dsn.

Renamed the env field 'Svc' to 'StorageService'.

Changing back to the old working directory was executed by defer and its
error was thus ignored. defer is now wrapped in an anonymous function
where a potential error will be handled.

Cobra and Viper make you use global variables and init functions. So we
have to ignore the two linters in the cmd package.

Remove pkg directory and move its content to the root of the project.

Add an optional description with a maximum length of 255 characters.

Even though its not really useful; the name is used to create a project
so it should probably be stored too.

Replace the functions LoadAllClasses and LoadAllProjects with
LoadClasses and LoadProjects. The new functions take a spread string
array as parameter. If one or multiple inputs are given, the function
returns one or multiple classes/projects. If no input is given all
classes/projects will be returned.