Igniter and Pype bootstrap improvements

[antirotor]

Feature

This refactor functions used to create and install Pype version via Igniter. Including few UI improvements and stopping start.py to load environments from settings until proper Pype version can be determined.

[rjmoggach]

On first run would be great to have some more verbosity on documentation/tooltips...
What is the studio root?
What is the repo url?
What is the mongo connection string?
Eg. mongodb+srv://pype:<password>@db.studio.lan/pype

Further to that... (and OT) setting up DNS SRV records is always lovely for mongo

[mkolar]

The documentation will come once the beta is out. It was still changing quite a lot until now.

mongo you got right
Repo URL is path to a folder where studio stores zips of pype version for arts

[antirotor]

Added option to run Pype without installation

[iLLiCiTiT]

Issues I found out

• ~/igniter/tools.py function get_pype_path_from_db expect that there is "global_settings" document in mongo
• directory in built pype "~/<build folder>/lib/" is added to environment PYTHONPATH which breaks all python hosts as it overrides default python modules
• seems like startup scripts are not executed on host start (didn't look for a reason much)
  • NOTE: We set startup scripts to both avalon and pype paths which does not make sence as what happens in pype's startup should happen on avalon's host installation (which also install pype's host) or we should not start avalon's startup script at all. We should use avalon script or pype script, not both. This is not issue of this PR.