- Updated container recipes
- Updated overlay templates
- Cleaned iPXE output

Fixes for: #346

**Refactors**
* Combine server response handling, reduce code duplication
* Simplify stage cases, backward compatible uri
* Implement image creation as functions instead of shell scripts
* Combine daemonLogf and wwlog to single logging output
* Switch to named wwlog functions instead of constants

**Fixes**
* Fix hidden errors occurring in shell pipes
* Fix kernel search path for Ubuntu
* Fix http response when template rendering fails
* Fix template newline insertion, update dhcp and hosts tmpl

**Updates**
* Add hwaddr and interface to dhcp
* Add control over image compression to client
* Update IPXE template to handle non-compressed files
* Update DHCP template to set network interfaces and server IP assignment
* Update DHCP/hosts templates to choose a host-name self-consistently