add major version to module path, sync module name with repo's

[consolethinks]

Description

According to official Go guidelines, we need to add the major version to the module path in order for people to be able to include the package as a dependency. They also recommend to create separate branches for major releases, but that's optional.

[consolethinks]

As an additional note, here's what happens if I try to include v3.0,0 in a different module without the module name change:

[sbliven]

It's good to follow the golang best practices.

Looking at managing source it looks like the directory structure should match the full module name. So should it be moved to eg github.com/paulscherrerinstitute/scicat-cli/cmd?

[consolethinks]

It's good to follow the golang best practices.

Looking at managing source it looks like the directory structure should match the full module name. So should it be moved to eg github.com/paulscherrerinstitute/scicat-cli/cmd?

@sbliven
The module encompasses the cmd, datasetUtils, datasetIngestor packages, so no change is needed because of that. However, since the module name is now scicat-cli/v3, we could move all packages into a v3 subfolder if you think that works better.

Personally, I prefer the solution of creating a new v3 branch, and then we could revert main to a pre-v3 state. However, main will still be technically non conformant as its module name does not include /v2 at the end, nor does it have its files in a v2 subfolder, nor does it use a v2 branch.

References on best go language practices regarding major version bumps:
https://stackoverflow.com/questions/70058951/project-structure-with-v2-go-modules
https://go.dev/wiki/Modules#releasing-modules-v2-or-higher