Revise user agreement and remove ScratchX terms

[rosics-code]

Updated user agreement and license references to Creative Commons Attribution-ShareAlike 4.0. Removed Appendix B related to ScratchX.

Resolves:

ScratchX website has been not working for YEARS.

Changes:

I revised a section since it mentioned ScratchX and it had to make sense. I made 2.0 license 4.0 since it has the ability to do adaptations in 4.0.

[rosics-code]

@adzhindzhi maybe look at this?

[adzhindzhi]

Hey @rosics-code, thank you for contributing! While the changes look good to me, I think updates to the Terms of Use page have to go through the legal team first.

@cwillisf What do you think?

[mrsrec]

@adzhindzhi The footer on scratch-www pages no longer links to the TOU page in this repo, and instead links here : https://mitscratch.freshdesk.com/en/support/solutions/articles/4000219182-scratch-terms-of-use - however, that link has these same problems. However, the scratchr2 footer still does link to this page.

In my opinion, that link is not exactly easy to remember, and also shouldn't be pointing to an external site. Keeping the terms on either scratch.mit.edu or scratchfoundation.org would be better; I kind of assumed it was already a done deal to move it, but since you're still apparently accepting PRs for this, should the footer link be changed back to point to the one that rosics-code is changing here?

[rosics-code]

@adzhindzhi The footer on scratch-www pages no longer links to the TOU page in this repo, and instead links here : https://mitscratch.freshdesk.com/en/support/solutions/articles/4000219182-scratch-terms-of-use - however, that link has these same problems. However, the scratchr2 footer still does link to this page.

In my opinion, that link is not exactly easy to remember, and also shouldn't be pointing to an external site. Keeping the terms on either scratch.mit.edu or scratchfoundation.org would be better; I kind of assumed it was already a done deal to move it, but since you're still apparently accepting PRs for this, should the footer link be changed back to point to the one that rosics-code is changing here?

There seems to be 2 terms of use in the file for the footer..

[rosics-code]

@mrsrec @adzhindzhi I made a file change.