setupEnv: add deps.txt for every instance.

[Vipon]

Well known dependencies should be specified locally in directory with install.py scripts of instance.

It's allow users don't worry about this dependencies and concentrate on deps for their own project.

At the same time, if users need to add new deps to existed instance, they can do it via adding deps to main deps.txt or update instance specific deps.txt files. The first way should be preferable, because it's allow them to checkout setupEnv new versions without conflicts.

[Vipon]

If main deps.txt and instance specific deps.txt contain same instances:

• version will take from main deps.txt
• install directory will take from main deps.txt
• dependencies will be combined from all files