kubectl-config: add page

[vanvuvuong]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known):

[tldr-bot]

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

pages/common/kubectl-config.md:3: TLDR004 Command descriptions should end in a period
pages/common/kubectl-config.md:4: TLDR004 Command descriptions should end in a period
pages/common/kubectl-config.md:5: TLDR004 Command descriptions should end in a period

Please fix the error(s) and push again.

[gutjuri]

Thank you for you contribution! I made some suggestions below :)

[vanvuvuong]

Thank @gutjuri , I just updated all your suggestions.

[kbdharun]

LGTM, Thanks for your contribution.