Support for remote file opening when connecting to other than 'localhost'

[boltex]

Support remote file opening to stabilize usage from connections coming from outside of 'localhost'.

For now, LeoInteg "open-file browser" is just vscode's utility 'open-file-dialog', that offers to choose locally. A remote server would not see the chosen file, and fail opening anything.

TODO:

1- Differentiate connection IP to detect if not connected to localhost
Use when:
a) calling 'open file' command.
b) when trying to reopen last opened files at startup.
c) Also block/allow opening local Leo files with right click in explorer.

2- Offer remote files selection dialog when open file command executes with remote.

3- Modify startup procedure to prevent opening last opened local files if connecting to a remote server. (Maybe save recent files with server address association, to only try to reopen those where connection address match with the right method).

[boltex]

Also needs to continue listening for subsequent connections after a "client disconnect" is detected, instead of exiting script.

[boltex]

@edreamleo This is also an indirect issue for leoserver now part of the Leo project itself. I'll add more descriptive details about this when I convert leoInteg to specifically use leoserver from the Leo editor instead of the old leoBridgeServer.