Polish dev experince for Spring projects

[Eskibear]

Scaffolding (Spring Initializr)

• Open HELP.md for newly created projects vscode-spring-initializr#206
• Show corresponding document link when selecting dependencies. add links onto starter candidates vscode-spring-initializr#211
• Use QuickPickItemKind.Separator to separate different group of starters. add separator between starter groups vscode-spring-initializr#210
• Support to create projects from Spring Guides.

Authoring

• Better completion for properties vscode-maven#843

Management

• dashboard not working when actuator is not a dependency of the project vscode-spring-boot-dashboard#193

[nickzhums]

Please use internal doc as reference: https://microsoft.sharepoint.com/:w:/r/teams/IoTToolingTeam/_layouts/15/Doc.aspx?sourcedoc=%7B161A03F7-1408-478D-B952-7BB85B76E547%7D&file=Spring%20enhancement%20on%20VS%20Code%20Java%20extensions.docx&action=default&mobileredirect=true&share=IQH3AxoWCBSNR7lSe7hbduVHAXjBCz2LsRsuhvJU2fNzoRQ

There are features in the doc that we discussed and we talked about their priorities

[Eskibear]

Closing as completed. The scoped linked issues are complete, and the remaining scaffolding item was dropped.