Improve docs

[moribvndvs]

Please check if the PR fulfills these requirements

• [x] The commit message follows our guidelines: https://github.com/moribvndvs/ng2-idle/blob/master/CONTRIBUTING.md#pr
• [x] Tests for the changes have been added (for bug fixes / features)
• [x] Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x")

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[x] Other... Please describe: Add living docs project using latest package versions + scripts for automation

What is the current behavior? (You can also link to an open issue here)

Docs project is kept in a separate repo, has to be updated and copied manually, and is woefully out of date.

What is the new behavior?

Docs project moved in-repo and symlinks to keepalive/core so it's always using the most recent version.

Does this PR introduce a breaking change? (check one with "x")

[ ] Yes
[x] No

If this PR contains a breaking change, please describe the impact and migration path for existing applications: ...

Other information:

[moribvndvs]

Hey @worksoncloud let me know if you like this approach. We'll want to expand the docs with other examples but its good enough for now IMO.

I think I just need to update the release script to build and commit the updated docs. I considered having CI do it but I think that's too noisy, and it should happen at the same time we release (which is currently a manual task from the command line using lerna ala npm run release and entering the OTP for publishing to NPM).

[coveralls]

Coverage remained the same at 100.0% when pulling cdc4197dedffb282ad22d836da621c3744897201 on improve-docs into 7de968d4fb3727ef37c718bb03557e37100daba9 on master.