Add a creative commons 4.0 license

[mxgrey]

It was pointed out by #109 that we are currently missing a license for the content in this repo. This was a simple oversight that happened during the initial creation of the repo, and it has flown under the radar until now.

The absence of a license was never intentional, but after so many contributions have already happened, it would be inappropriate to unilaterally add a license without the consent of prior contributors. After some internal discussions we concluded that CC-BY-4.0 is the right license for the repo, so now we're seeking consent on that from everyone who has contributed.

I'm tagging everyone who has made a substantial contribution (excluding non-content contributions like grammatical fixes). If every substantial contributor gives explicit consent, we'll merge immediately. Otherwise we will wait until 23 August 2024 to see if any past contributor raises an objection. If we receive no objections by EOD anywhere in the world of that date, then we will assume consent. This is a reasonable assumption since all other documentation repos by OSRF are also licensed under CC-BY-4.0, and all contributors knew that they were contributing to an OSRF project.

If you are tagged below, kindly indicate consent by commenting with a 👍 or leave a comment objecting along with the rationale for your objection.

@mdfesto
@Yadunund
@codebot
@aaronchongth
@thedevmanek
@kscottz
@gbiggs
@xiyuoh
@youliangtan
@maryaB-osr
@marcoag

[kscottz]

👍👍 🐀