feat(yamllint): include for this repo and apply rules throughout

Semi-automated using ssf-formula (v0.5.0)
Fix errors shown below:

vault-formula$ $(grep "\- yamllint" .travis.yml | sed -e "s:^\s\+-\s\(.*\):\1:")
./kitchen.yml
  20:89     error    line too long (96 > 88 characters)  (line-length)

./vault/defaults.yaml
  4:1       warning  missing document start "---"  (document-start)
  9:13      warning  truthy value should be one of [false, true]  (truthy)
  10:20     warning  truthy value should be one of [false, true]  (truthy)
  12:14     warning  truthy value should be one of [false, true]  (truthy)

./vault/osfamilymap.yaml
  4:1       warning  missing document start "---"  (document-start)

./vault/initfamilymap.yaml
  4:1       warning  missing document start "---"  (document-start)

pillar.example
  4:1       warning  missing document start "---"  (document-start)
  7:13      warning  truthy value should be one of [false, true]  (truthy)
  8:20      warning  truthy value should be one of [false, true]  (truthy)
  54:1      error    too many blank lines (1 > 0)  (empty-lines)

test/salt/pillar/install_binary.sls
  1:1       warning  missing document start "---"  (document-start)
  2:89      error    line too long (110 > 88 characters)  (line-length)
  4:20      warning  truthy value should be one of [false, true]  (truthy)

test/salt/pillar/dev_server.sls
  1:1       warning  missing document start "---"  (document-start)
  2:13      warning  truthy value should be one of [false, true]  (truthy)

test/salt/pillar/prod_server.sls
  1:1       warning  missing document start "---"  (document-start)
  8:14      warning  truthy value should be one of [false, true]  (truthy)

Refer back to: https://github.com/saltstack-formulas/template-formula/pull/159#issue-305203039.

saltstack-formulas / vault-formula

feat(yamllint): include for this repo and apply rules throughout #38