To avoid having to specify each spec by hand (which can miss specs to be
added), the test infrastructure now performs classpath discovery so that
each spec added, is automatically considered.
Relates #40358
(cherry picked from commit d0f60b4425c731509aa8ca765d55f563f866ef90)
* New OCTET_LENGTH function
* Changed the way the FunctionRegistry stores functions, considering the alphabetic ordering by name
* Added documentation for the RANDOM function
* Changed the format of the String functions documentation page.
* Adopted the same format for Math functions, but completely changed the examples.
* Added missing documentation for Math functions.
Split function section into multiple chapters
Add String functions
Add (small) section on Conversion/Cast functions
Add missing aggregation functions
Enable documentation testing (was disabled by accident). While at it,
fix failing tests
Improve spec tests to allow multi-line queries (useful for docs)
Add ability to ignore a spec test (name should end with -Ignore)