Glossary: add Summary, add Implementation, change Exercise

[Insti]

Update glossary based on discussion in: https://github.com/exercism/discussions/issues/145

Which helped settle on definitions for: Specification, Implementation, Exercise and Problem

Added: Summary section, Definition of implementation Changed: Exercise

I also added the summary here, I'm not sure if this is the best place for it, but figured it could be moved somewhere more appropriate once that place is identified.

Meta note: I really don't like how the table formatting makes the diffs noisy.

[kytrinyx]

I also added the summary here

I like having it here.

[kytrinyx]

Meta note: I really don't like how the table formatting makes the diffs noisy.

It also means we're going to have some interesting conflicts. Both of the open pull requests at the moment edit the table.

[Insti]

Both of the open pull requests at the moment edit the table.

Oops, I didn't see that one, I'll resolve conflicts if it gets merged.

[kytrinyx]

@Insti I went ahead and merged the regex PR to the glossary.md. Would you rebase when you have a chance?

[Insti]

Done. I tried to split the table reformatting from the major changes so these are visible in separate commits.

[kytrinyx]

🌷 Thank you!