This is consistent with the way BackRest and BackRest test were renamed way back in 18fd2523.
More modules will be moving to pgBackRestDoc soon so renaming now reduces churn later.
This directory was once the home of the production Perl code but since f0ef73db this is no longer true.
Move the modules to test in most cases, except where the module is expected to be useful for the doc engine beyond the expected lifetime of the Perl test code (about a year if all goes well).
The exception is pgBackRest::Version which requires more work to migrate since it is used to track pgBackRest versions.
This was the interface between Perl and C introduced in 36a5349b but since f0ef73db has only been used by the Perl integration tests. This is expensive code to maintain just for testing.
The main dependency was the interface to storage, no matter where it was located, e.g. S3. Replace this with the new-introduced repo commands (d3c83453) that allow access to repo storage via the command line.
The other dependency was on various cfgOption* functions and CFGOPT_ constants that were convenient but not necessary. Replace these with hard-coded strings in most places and create new constants for commonly used values.
Remove all auto-generated Perl code. This means that the error list will no longer be maintained automatically so copy used errors to Common::Exception.pm. This file will need to be maintained manually going forward but there is not likely to be much churn as the Perl integration tests are being retired.
Update test.pl and related code to remove LibC builds.
Ding, dong, LibC is dead.
The tests and documentation have been using the core storage layer but soon that will depend entirely on the C library, creating a bootstrap problem (i.e. the storage layer will be needed to build the C library).
Create a simplified Posix storage layer to be used by documentation and the parts of the test code that build and execute the actual tests. The actual tests will still use the core storage driver so they can interact with any type of storage.
