fix: show configured SSH hosts in Connect to Host picker

[aloknew157]

Summary

• load configured hosts from the parsed SSH config before prompting
• show a quick-pick list of configured hosts
• keep manual [user@]hostname[:port] entry as a fallback

Why

• Remote-SSH: Connect to Host... currently opens a plain input box even when SSH hosts are already configured
• This makes the command inconsistent with user expectations and matches the symptom reported in Open Remote SSH v0.1.1 on VSCodium 1.116 — No hosts shown from SSH config #272.
• This PR fixes Fixes Open Remote SSH v0.1.1 on VSCodium 1.116 — No hosts shown from SSH config #272

[daiyam]

• Remote-SSH: Connect to Host... currently opens a plain input box even when SSH hosts are already configured

Yes, because you can directly type the host name (like host1). It's fast for those who know their hosts.
Those who prefer UI, can use the Remote Explorer panel.

Maybe,

• the current Remote-SSH: Connect to Host... can be renamed Remote-SSH: Type Host and Connect...
• the command with the quick pick Remote-SSH: Select Host and Connext...

[GitMensch]

Why not using a single one with both string input and picker?

[daiyam]

Why not using a single one with both string input and picker?

Not sure if it's possible. I did the issue few years back, maybe it has changed.
@aloknew157 can you take a look into it? Thx

[daiyam]

Oh! duplicate of #255...