Translate section title in Japanese

[cstoku]

This is a...

• Feature Request
• Bug Report

Problem:
Some section titles aren't Japanese.

Proposed Solution:
Translate section title in Japanese.
Copy from en contents and update the files listed below.

• content/ja/docs/_index.md (ja-trans: add docs/_index.md #11422, ja-trans: add docs/_index.md (cherry-pick from dev-1.12-ja.1) #11721)
• content/ja/docs/home/_index.md (Translate content/ja/docs/home/_index.md in Japanese #11569)
• content/ja/docs/setup/custom-cloud/_index.md (Translate content/ja/docs/setup/custom-cloud/_index.md in Japanese #11572)
• content/ja/docs/setup/independent/_index.md (ja-trans: Translate setup/independent/_index.md #11573)
• content/ja/docs/setup/on-premises-vm/_index.md (Translate content/en/docs/setup/on-premises-vm/_index.md in Japanese #11574)
• content/ja/docs/setup/release/_index.md (Translate content/ja/docs/setup/release/_index.md in Japanese #11576)
• content/ja/docs/setup/turnkey/_index.md (Translate content/ja/docs/setup/turnkey/_index.md #11582)
• content/ja/docs/tutorials/kubernetes-basics/create-cluster/_index.md (ja-trans: Translate content/ja/docs/tutorials/kubernetes-basics/create-cluster/_index.md in Japanese #11575, ja-trans: Translate content/ja/docs/tutorials/kubernetes-basics/create-cluster/_index.md in Japanese #12059)
• content/ja/docs/tutorials/kubernetes-basics/deploy-app/_index.md (Translated Tutorials/Learn Kubenetes Basics/Deploy an App in Japanese. #11583)
• content/ja/docs/tutorials/kubernetes-basics/explore/_index.md (ja-trans: Translate content/ja/docs/tutorials/kubernetes-basics/explore/_index.md in Japanese #11580)
• content/ja/docs/tutorials/kubernetes-basics/expose/_index.md (trans-jp: tutorials/kubernetes-basics/expose/_index.md #11584)
• content/ja/docs/tutorials/kubernetes-basics/scale/_index.md (Dev 1.13 ja.1 tutorials kubernetes basics scale #11577)
• content/ja/docs/tutorials/kubernetes-basics/update/_index.md (Translate content/ja/docs/tutorials/kubernetes-basics/update/_index.m… #11579)

Page to Update:
Several pages including TOC.

[bells17]

content/ja/docs/home/_index.md
こちらやります
#11569

[bells17]

content/ja/docs/setup/custom-cloud/_index.md
こちらやります
#11572

[hhiroshell]

content/ja/docs/tutorials/kubernetes-basics/create-cluster/_index.md
こちらやりまっす。
#11575

[lkougi]

content/ja/docs/setup/independent/_index.md
これやります！

[bells17]

content/ja/docs/setup/on-premises-vm/_index.md
こちらやります
#11574

[bells17]

content/ja/docs/setup/release/_index.md
こちらやります
#11576

[hmaruyama]

content/ja/docs/setup/turnkey/_index.md
こちらやります！
#11582

[dzeyelid]

content/ja/docs/tutorials/kubernetes-basics/deploy-app/_index.md
こちらやります！