Clang warned about the code removed in this patch with the warning:
```
warning: out-of-line definition of constexpr static data member is
redundant in C++17 and is deprecated [-Wdeprecated]
```
* Add a new operating mode to rippled called reporting mode
* Add ETL mechanism for a reporting node to extract data from a p2p node
* Add new gRPC methods to faciliate ETL
* Use Postgres in place of SQLite in reporting mode
* Add Cassandra as a nodestore option
* Update logic of RPC handlers when running in reporting mode
* Add ability to forward RPCs to a p2p node
* Jobs with no unit tests are counted as failures. Resolves#3474
* Crashed processes are counted as failures. Resolves#3600
* Any tests specified on the command line test do not have matching
suites are counted as failures.
* Remove unused CI manual test.
When a test suite starts and ends, it informs the parent process. If the parent
has received a start message without a matching end message it reports that a
child may have crashed in that suite.