Optimize RAM usage by lsif_transformer/parser
We load into RAW a lot of data in order to link ranges with hovers and definitions: !492 (comment 338417461). As a result, about 100mb of RAM is required for processing 100mb file.
Currently, we limit the size of a LSIF file to be processed to 20mb (zipped, 180mb raw) in order to restrict RAM usage.
One of the approaches that we can take is to store an intermediate state in a file. We've already done it for hovers and store large documentation data in a file and store the links to that data in the memory.