pg_receivewal: add page

[Anirban-Chand]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR contains at most 5 new pages.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known):

[CLAassistant]

All committers have signed the CLA.

[Managor]

Apply this to the whole page

[Managor]

Suggested change

	`pg_receivewal -D {{directory}}`
	`pg_receivewal {{[-D|--directory]}} {{directory}}`

Do not use short options by themselves when long options are available