DOCS: Document Kerberos

Signed-off-by: kay <kay.kim@10gen.com>
DOCS-2188 kerberos pass 1
trivial: remove extraneous whitespace in examples
DOCS-2353 maxDistance in the near doc and non-negative value
DOCS-2339 enable authentication on a mongodb instance

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-2339 enable auth: add second tutorial

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-2339: edits mostly for parallelism, and no-op steps formating
minor: fixing syntax error
DOCS-2699: adding reference to admin.system.version
Removing double 'operator' term

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-2766 nUpdated to nMatched
DOCS-2609: edits to enforce uniqueness to clarify behavior
DOCS-2732: finishing dangling sentence
minor: fixing word order
DOCS-2732: clarifying sentence
DOCS-2433: adding backup link
DOCS-2652 reword definition of exists operator

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-2670 new steps format: enable auth in sharded and generate key file

Signed-off-by: Sam Kleinman <samk@10gen.com>
minor wording edits for DOCS-2670
minor: fixing wording. thanks @merids!