Fix a typo and note Pierre Roux's comment on disjuctions vs inductives.

See also: RT-PROOFS/rt-proofs#54 (comment 42229)

In anticipation of future reorganization efforts by Sophie, there's no
point in keeping the two kinds of definitions separate.

Move everything into the new namespace starting with 'prosa' rather
than the bland 'rt'.

The main restructuring thrust is nearing completion, so let's get rid
of the `restructuring` namespace.

improve comments, fix names, move some stuff around

spell checker: add 'supremum' to dictionary

...and define a job's total suspension time.

For improved parallelism and nicer documentation.

This is not yet the final organization, but already an improvement.

Move main high-level results to separate top-level `results` module.
Rationale: Let's make it very clear where to find the main, high-level
results in Prosa, and at the same time let's declutter the analysis
namespace.

Other notable change, apart from moving files around:

- move two key analysis definitions to analysis.definitions
- split RBF definition and facts into separate files
- move facts about ideal schedule to ideal_schedule.v

While at it, clean up some Markdown rendering issues on Gitlab.

Job-level definitions should not depend on task-related modules.

The notion of a valid preemption model for *jobs* should
not depend on any task abstraction. Split the two notions.