This reverts commit acfd6318.

# Conflicts:
#	resources/src/META-INF/IdeaPlugin.xml

This reverts commit 1d039f98

This reverts commit 72de6a1f

make it an implementation detail which no one should depend on
we want stubs from multiple roots to be managed as independently as possible

ideally, the serialization + index query API should return several stub lists,
but that's too many new methods, maybe we'll add them in future

Fix stepping after error jump, fix tests, move code modification to an appropriate function and make it more general

by reusing the logic from "Convert to variable annotation" intention

This change also partially remedies the problem described in PY-28879
when the whole file was parsed whenever we found typing.Tuple in a
variable type comment, because we no longer transform type hints like
"int, str" into "Tuple[int, str]" as an intermediate step and process
them right away instead. We still need to handle general type comments
with unpacking in stub-safe manner, though.

for manual testing (of showing TB-buttons)

fixed: TODOs, memory management (ref-count with autorelease pool), move code into proper packages

fixed: TODOs, memory management
add initial gradle script (to build libnst manually)