CASSGO-29, refactor packages to separate internal and public API

[OleksiienkoMykyta]

Closes #465

[OleksiienkoMykyta]

@joao-r-reis could you please check the PR

[joao-r-reis]

I like this a lot 👍 it's a very good foundation so that future code can be written with this internal vs public structure in mind and doesn't change anything on the public API.

Anything more than this at a single time will require a lot of effort and I think doing things this way with small steps at a time will work better 👍

[OleksiienkoMykyta]

I like this a lot 👍 it's a very good foundation so that future code can be written with this internal vs public structure in mind and doesn't change anything on the public API.

Anything more than this at a single time will require a lot of effort and I think doing things this way with small steps at a time will work better 👍

Great. So, I will clean up a little bit, and we can push it to merge, or we keep developing this PR? I think that merging would be better, to avoid future conflicts with new features, anyway its a good start point.
Thank you for the review, I appreciate it!

[OleksiienkoMykyta]

@joao-r-reis, I have upgraded it a little, but I think we should pause it until big PRs are merged, such as CASSGO-1, CASSGO-4, etc.
Also, it would be nice to do it in pieces, to prevent suсh long blockages.
wdyt?

[joao-r-reis]

Honestly it might even be worth delaying this until 2.1 release, we don't want to do any api breaking changes with this PR anyway

[joao-r-reis]

Also I thought this PR was already good enough to merge, I have to retract my +1 until I can review it again since you made some changes

[OleksiienkoMykyta]

Also I thought this PR was already good enough to merge, I have to retract my +1 until I can review it again since you made some changes

Oh, sorry. I thought that we should move everything that doesn't expose to a user to the internal package in this PR, because there are a lot of things left to move.