couchdb: add page

[lamar-frankie]

---

• [ x] The page (if new), does not already exist in the repo.

• [x ] The page (if new), has been added to the correct platform folder:
  common/ if it's common to all platforms, linux/ if it's Linux-specific, and so on.

• [ x] The page has 8 or fewer examples.

• [ x] The PR is appropriately titled:
  <command name>: add page for new pages, or <command name>: <description of changes> for pages being edited

• [ x] The page follows the contributing guidelines

Closes #1175

[tldr-bot]

The build for this PR has failed with the following error(s):

pages/common/couchdb.md:36: TLDR008 File should contain no trailing whitespace

Please fix the error(s) and push again.

[agnivade]

Some general comments before we dive in further.

• Start with the simplest invocation first. Just couchdb.
• The page seems too long. We should trim it down a bit, maybe up to 6 examples would be good.
• There should be a natural flow to the examples. Regarding the killing of background process, start with the -b option, which spawns a background process, then move on to -k which kills it, and then -d, which shuts it down.

In general, think about which options are not necessary, and which options are required for a beginner to get started. Accordingly update the page.

[lamar-frankie]

I simplified the page. I think all the commands that remain are pertinent.
Start couchdb
Launch shell
Start in the background
Kill
Shutdown

[agnivade]

@lamar-frankie - made a minor change. Let me know if this looks good to you.

[sbrl]

Looks good to me! Thanks, @lamar-frankie 😺