v1.4.0: Read config from env vars and quite a few bugfixes (Kathleen Booth)

Features:

• Adds config option 'track_vm_host' to vmware source #235
• Adds config option to define where the cache files should be stored #254
• Adding Dell ServiceTag as custom field from check_redfish inventory import #265
• Adds config option to disable interface name overwrite during snyc #175
• Enable setting ip_tenant_inheritance_order with import_inventory #281
• Adds config option 'sync_vm_interface_mtu' to vmware source #261
• Adss reading of ENV vars and yaml files for configuration #227
• Adds new cli option -g to autogenerate config files #227

Bugfixes:

• Switch from 'uuid' to 'instanceUUID' to track already synced VMs #246
• Fixed FHRP Netbox object malformed api_path #233
• Fixes issue with redfish ps maximum_draw < 1 #244
• Fixes parsing of meta.inventory_id in redfish source #244
• Mitigate json decoder error with newer requests libraries #251
• Fixes issues with long running jobs and closing connection errors #248
• Fixes issue with IP address changes on same device #193
• Fixes issue with moving ip addresses from device a to b if ip address is primary ip of device #224
• Fixes issues with reassignment of IP addresses not honoured properly #224, #179
• Fixes pruning and handling objects from unknown sources #273

Maintenance:

• Complete refactoring of config parsing to support ini and yaml files and reading from environment as well.

Thanks to @zvfvrv for the contributions and PRs. As well to @rizlas for all the testing and patience.