[WIP] Add v1alpha3 for ClusterFilter

[frankgreco]

What this PR does / why we need it:

Adds a new version, v1alpha3, for the fluentbit group. The ClusterFilter resource is then added to this group.

TODO

- Implement the conversion functions
- Testing

Notes:

- The kubebuilder documentation was followed for (1) v1alpha3/ClusterFilter creation (2) conversion (3) webhook
- v1alpha2/ClusterFilter was not created correctly prior to this PR (it was not present in PROJECT)
- main.go was not located in the correct place. The kubebuilder project REQUIRES it be a the root with no override option.
- I guess you don't need to copy over all of the types in the new version, just the types that you actually need to break. This is cool.
- I cleaned a hacky way were were referencing `generate-group.sh`. I replaced it with the go native way to do it.
- Used the appropriate `tools.go` pattern to ensure we store tooling deps in `go.mod`.

Which issue(s) this PR fixes:

Fixes #309

Does this PR introduced a user-facing change?

- A new version (v1alpha3) has been created for the ClusterFilter resource.

Additional documentation, usage docs, etc.:

TBD

[frankgreco]

@benjaminhuo @wenchajun I still need to implement the conversion function but this should be ready for a first pass.

[frankgreco]

An outstanding question I have is if we really have to do all the copy/pasting.... I tried using aliases but I don't think kubebuilder likes those very much although I still have more testing to do.

[benjaminhuo]

Close it for now because of inactive