Update hello-planning-guide.md + MD improvements

Description:
As agreed upon in issue ticket #4875, the line
"> This guide only applies to Windows 10, version 1511 or higher."
should be removed because it imposes an outdated build.

Thanks to mapalko for requesting this removal, and to poortom1004
for pointing out the version redundancy in the first place.

Proposed changes:
- Remove the aforementioned line, as agreed upon
- Add recommended single MarkDown quote spaces
- Replace a tab with standardized spacing
- Remove redundant white space in 3 blank lines

issue ticket closure or reference:

Closes #4875

windows/security/identity-protection/hello-for-business/hello-planning-guide.md

@@ -21,8 +21,6 @@ ms.reviewer:
 **Applies to**
 -   Windows 10
 
-> This guide only applies to Windows 10, version 1511 or higher.
-
 Congratulations! You are taking the first step forward in helping move your organizations away from password to a two-factor, convenience authentication for Windows — Windows Hello for Business. This planning guide helps you understand the different topologies, architectures, and components that encompass a Windows Hello for Business infrastructure.
 
 This guide explains the role of each component within Windows Hello for Business and how certain deployment decisions affect other aspects of the infrastructure. Armed with your planning worksheet, you’ll use that information to select the correct deployment guide for your needs.