Allow multiple set-cookie headers (#51)

Set-cookie headers gotta be separate, it's a special case...

X-Forwarded-Host to contain full linkup domain (#50)

Use the full linkup domain as X-Forwarded-Host. This is "truer" to the
standard, should still work with the rest of the linkup session
detection functions, and makes some next features work for us.

feat: create preview command (#47)

co-author: @ostenbom 

### Description
This adds a command to linkup-cli and an endpoint to linkup worker so
that a whole "persisted" session can be created.

Allow large payloads in local server

Auto-release 0.1.20

Test auto-release 0.1.19

Linkup 0.1.16

Linkup 0.1.15

Fix local dns websockets

Boot local before tunnel