Feature request: Separate versions per extension

[l0b0]

Is your feature request related to a problem? Please describe.

Currently each extension has the same version number. This is problematic:

• It's not possible to do semantic versioning this way.
• Most version bumps so far involve fewer than all the extensions, and it's probably safe to say that most future version bumps will involve only a single extension. So most releases of each individual extension will have no changes at all.
• The change log is global, meaning that changes to each individual extension is mixed with all the other changes. This makes it difficult to work out which changes are relevant when looking at a single extension.

Describe the solution you'd like

• Each extension should be released separately, starting at whatever version is current at the time of implementation.
• Each extension should have its own change log, with only changes relevant to it.
• The directory structure of released extensions, currently VERSION/NAME, should be reversed into NAME/VERSION, because version N of each extension is unrelated to the same version N of each other extension.

Describe alternatives you've considered

Splitting up the extensions into separate repositories will make this trivial, at the expense of having either duplicated content (at least the unit testing setup and shell.nix) or having to pull out a repository with common content.