First cut at license stuffs

[aboodman]

This change licenses repc as Business Source License (BSL).

BSL is a "parameterized" license. It allows usage subject to a set of specified restrictions initially, then falls back to pure open source as of a "change date".

You can read some background on Business Source License here:

https://mariadb.com/bsl-faq-adopting/ https://blog.adamretter.org.uk/business-source-license-adoption/

There are various interesting questions around how to use BSL:

What should the "Additional Use Grant" be?

I looked for inspiration at what the following projects did and adapted them:

• https://github.com/zerotier/ZeroTierOne/blob/master/LICENSE.txt
• https://mariadb.com/projects-using-bsl-11/

I think we will eventually want to get a lawyer to look at this bit but I think this is OK as a start (we can always tighten it later).

How far in the future should the "Change Date" be?

Most BSL projects to date use Change Dates that are 3 or 4 years from time of publish. This feels too long to me so I'm proposing 2 years to start.

How often should the "Change Date" be updated?

Most projects bump the change date with either major or minor versions. I'd ideally like to do it with every commit, but I could not find an example of that in the community so I propose we do what CockroachDB does and bump it with minor versions (but not patch versions).

[aboodman]

This is ready for review now. Check out the tool bump.go