Asynctelnet for... science! Weird priv levels for... reasons! Plus also more things!

• Make log messages for textfsm and genie parsers failing to parse consistent as log.warning
• Add factory example
• Add "root" priv level to junos driver -- probably should be considered experimental for now :)
• Fix issue where send_config unified result did not have finish time set
• POSSIBLY BREAKING CHANGE: logger names have changed to be easier to get/make more sense -- the logger for each instance used to look like: "scrapli-channel-{{ HOST }}" which kinda was not really smart :). Loggers now look like: "scrapli.{{ HOST }}:{{ PORT }}.channel" -- can be channel|driver|transport!
• Changes to test environment:
  • Support running devices on localhost w/ nat'd management ports -- in "vrouter" mode (poorly named) -- this is enabled with the SCRAPLI_VROUTER environment variable set to on/true/something
  • Added bootvar into nxos base config -- when missing causes qemu nxosv to boot into loader prompt so thats no good
  • Replace resource settings in vdc in nxos to account for nxos instances with differing resources (memory/cpu)
  • Got rid of static license udi in iosxe config, replaced more certificate stuff so show run comparisons are easier on iosxe
• NEW TRANSPORT asynctelnet transport is built using standard library asyncio, as such it is part of scrapli core
  • Should be considered beta for a while :)
  • Added a bunch of tests mocking streamreader/writer to ensure that this driver is well tested
• Added asynctelnet support in nxos and juniper drivers (to change prompt for those platforms)
• Support asynctelnet in base driver
• auth_bypass for both telnet drivers completely bypasses not only auth (as it did previously) but also the auth validation where we confirm we got logged in successfully -- reason being is that for console servers and such you may not care about that, you may just want to log in and read data.
• Removed unnecessary re-checking/verifying of ssh config file in system transport (was basically duplicated from base transport, so was pointless!)
• Bumped all the default timeout values up as they were probably a bit on the aggressive side
• Added eager argument to send commands/commands from file and config/configs/configs from file methods -- basically this eager mode will not look for a prompt between lines of commands/configs. This means that things have potential to get out of whack because we will just send things as fast as possible. In order to not totally break things we will (whether you like it or not!) wait and find the prompt on the last command/config in the list though -- that way we dont get too out of whack. This now means we can use eager to configure banners and macros and things and we no longer need to do the dirty send interactive workaround.
• Added ScrapliConnectionLost exception and raise it if we get EOF in system transport -- with a message that is more clear than just "EOF" and some obscure line in ptyprocess!
• Added tclsh privilege level for IOSXE
• Fixed a bug that would prevent going to "parallel" privilege levels -- i.e. going from tclsh to configuration or visa versa in IOSXE or from configuration to configuration_exclusive in IOSXR
• If no failed_when_contains is passed to send_interactive network drivers will now use the network drivers failed_when_contains attribute to bring it inline with the normal command/config methods
• Added timeout_ops to send_interactive and wrap those methods with the TimeoutModifier decorator
• Add logic to properly fetch socket address family type so we can handle IPv6 hosts (w/ scrapli-ssh2/scrapli-paramiko)
• Added tclsh privilege level for NXOS, didn't even know that existed before!