Describe a way how to migrate from cartridge-cli pack

There are several points that I faced during migration:

• Need to create tt.yaml file
• Need to specify env.instances_enabled in that config (expected behaviour is to be able to provide path to directory with a project as in cartridge pack app /path/to/project or choose current directory). BTW, I didn't find any mentions in doc (I found all info in tests).
• Recursive handling of pre/post build scripts. I had some scripts for performance tesing in depth of my project. It was unexpected that test/performance/<...>/cartridge.pre-build is handled somehow
• unzip requirement: Error: Failed installing dependency: /opt/tarantool-enterprise/rocks/metrics-1.0.0-1.all.rock - Failed unpacking rock file: /opt/tarantool-enterprise/rocks/metrics-1.0.0-1.all.rock: 'unzip -n' program not found. Make sure unzip is installed and is available in your PATH (or you may want to edit the 'variables.UNZIP' value in file '/etc/luarocks/config-5.1.lua')
• Strange message about Lua headers (they should be shipped as a part of Tarantool headers): Error: Failed finding Lua header files. You may need to install them or configure LUA_INCDIR.

Compare the migration from cartridge-cli pack with the current CLI behavior, starting with the existing documentation and the tests where the issue found configuration details. Document tt.yaml, env.instances_enabled, project-path handling, recursive pre/post-build scripts, the unzip requirement, and Lua header setup so users can complete the migration without relying on tests.