Move rand string func to util for reuse

Add a known issues doc.

Fixing examples_test for moved files in #11595

Added Project Calico networking plugin tutorial

Cleanup docs.

- Fix typo in services-firewalls
- Fix incorrect comma usage
- s/minion/node/
- Link deadlock to wikipedia article
- Fix livenessProbe capitalization
- Change API reference quoting from " to \`

Add some additional text about getting help.

Add upgrade instructions.

Split namespace docs user vs admin.

Move namespace.md and examples dir from docs/user-guide
to docs/admin.

Assumption is that creating and deleting namespaces is an "admin"
task.

Add a mostly new user-guide to namespaces that gives more advice
on when to use namespaces, and how to work within them,
but not how to create/delete them.  It is more succinct than
before.

Fix links in DESIGN.md

Remove equals from heading which breaks our links.

grammar fixes

Improvements to quota doc.

Improve scratch getting-started-guide.

Address review comments in #11487

Fix capitalization of Kubernetes in the docs

fixed 2 links, bit of text polishing

Fixing mark-new-version

Improve resource quota doc.

add admin index

Linking to API object definitions from docs

nop numbered list in doc to use manual numbering

Collected markedown fixes around syntax.

Update cluster management doc.