fix: Fix docker examples

- Moved `httpconnection` import from `clients` to `core`.
- Changed `tfgrid-sdk-ts` dashboard to playground.
- Added ipaddr to node_local().
- Added public keyword to OpenSSLGenerateArgs.
- Improved DockerEngine image and container loading.
- Added utils.contains_ssh_port.
- Improved error handling in DockerEngine.
- Improved Docker registry handling.

Co-authored-by: mariobassem12 <mariobassem12@gmail.com>
Co-authored-by: omda <mahmmoud.hassanein@gmail.com>

lib/threefold/rmb/rmb_client.v

@@ -1,6 +1,6 @@
 module rmb
 
-// import freeflowuniverse.herolib.clients.httpconnection
+// import freeflowuniverse.herolib.core.httpconnection
 import freeflowuniverse.herolib.core.redisclient { RedisURL }
 import os
 

lib/threefold/zerohub/zerohub.v

@@ -2,7 +2,7 @@ module zerohub
 
 import net.http
 
-// import freeflowuniverse.herolib.clients.httpconnection
+// import freeflowuniverse.herolib.core.httpconnection
 
 // TODO: curl -H "Authorization: bearer 6Pz6giOpHSaA3KdYI6LLpGSLmDmzmRkVdwvc7S-E5PVB0-iRfgDKW9Rb_ZTlj-xEW4_uSCa5VsyoRsML7DunA1sia3Jpc3RvZi4zYm90IiwgMTY3OTIxNTc3MF0=" https://hub.grid.tf/api/flist/