This commit extends the module API to support the addition of different
scripting engines to run user defined functions.

The scripting engine can be implemented as a Valkey module, and can be
dynamically loaded with the `loadmodule` config directive, or with
the `MODULE LOAD` command.

The current module API support, only allows to load scripting engines to
run functions using `FCALL` command.

In a follow up PR, we will move the Lua scripting engine implmentation
into its own module.

Signed-off-by: Ricardo Dias <[email protected]>

This commit adds a module with a very simple stack based scripting
language implementation to test the new module API that allows to
implement new scripting engines as modules.

Signed-off-by: Ricardo Dias <[email protected]>

Signed-off-by: Ricardo Dias <[email protected]>

Signed-off-by: Ricardo Dias <[email protected]>

Signed-off-by: Ricardo Dias <[email protected]>

…ORE|DELETE]

Signed-off-by: Ricardo Dias <[email protected]>

…ions.c`

Signed-off-by: Ricardo Dias <[email protected]>

… functionLibInfo in most places

Signed-off-by: Ricardo Dias <[email protected]>

- Removed the `ValkeyModuleScriptingEngineFunctionLibrary` structure.
- Changed a few structure and parameters names.

Signed-off-by: Ricardo Dias <[email protected]>

Signed-off-by: Ricardo Dias <[email protected]>

Signed-off-by: Ricardo Dias <[email protected]>

This commit creates a new unit for the scripting engine code by
extracting the existing code from the functions unit.

We're doing this refactor to prepare the code for runnning the `EVAL`
command using different scripting engines.

Signed-off-by: Ricardo Dias <[email protected]>