Related to #1153, implements the first part of the integration, without the
parts that use the runner which will be done next.
Temporarily there are two logger implementations - this will be alleviated with
the next part - when and the direct classpath dependency on the language server
is removed.
A bunch of improvements to the suggestions
system. Suggestions are extracted to the tree data
structure. The tree allows producing better diffs
between the file versions. And better diffs reduce
the number of updates that are sent to the IDE
after a file change, and consequently fix the
issue when the runtime type got overwritten with
the compile-time type.
