Additional `CodeChecker parse` requirements for VSCode IDE integration

[dkrupp]

In the CodeChecker VSCode plugin we would like to support the following use cases:

1. CodeChecker parse should show that a file was never analyzed
2. CodeChecker parse should show that the source file has changed since the last analysis
3. CodeChecker parse should show if a file has no compilation db entry
4. CodeChecker parse should show if an analys on a file errored on certain analyzers

Codechecker should record analysis results per file because currently analyzing a.c and then b.c in the same report dir overwrites the metada.json. The use case is that if a.c has a clang-tidy error and then we reanalyze b.c, we should be able to tell later what was the erorr with a.c.

CodeChecker parse should support json output for this information.