This is more of an exercise in QuickCheck than strong testing.

This completes the removal started earlier byt removeing the need to
pass the number of nodes to Node.buildPeers, which is now unused.

This patch adds a QuickCheck-based test infrastructure and initial tests
based on it. The PeerMap module has a 100% coverage ☺️

Side-note: one has to read the source of QuickCheck to see how to use it
(especially the Batch submodule), the docs are not enough…

This patch removes some unused functions and does some cleanup of the
remaining ones.

We remove some unused arguments (added way back for compatibility with
Arrays, which we didn't use in the end). This makes the code clearer
(and doesn't need the Ndx type to be an instance of Num).

Currently we (wrongly) use lookupNode to lookup instances, just because
the name assoc list has the same type. This patch adds a separate
function for it.

This is a first step towards full datatype renaming. That requires more
changes, so at first we only want to document clearly what is a node
index, what is an instance index, and what is a plain Int.

This patch makes the Types module a base module, and Node/Instance ones
import it, from the previous (opposite) situation. This will allow in
the future to use newtypes for the index and name types.

This splits the current “clean” rule into proper clean (cleaning of
build artifacts) and maintainer-clean (cleaning of distributed files).
This should make it better for Debian packaging.

The IAllocator source was copied from Rapi before the offline node fixes
were made. This changes such that offline nodes are accepted correctly.

Also replace tabs in an older entry with spaces.

Currently iallocator is broken when reading single-node instances (and
with an ugly error message). This patch fixes this case, by marking them
with secondary node “noSecondary” like the rest of the code.

This patch fixes the relocate-to-primary-node problem, and doesn't mark
the excluded nodes as offline anymore (we don't use them anyway, so
let's not use a different/fake cluster state).

Slash is a reserved char. Slash is a reserved char. Slash is a…

This patch implements filtering out of the offline/drained nodes and
fixes a bug in IAllocator.hs parsing (similar to an older bug in Rapi.hs
from where the code was copied).

This patch implements non-mirrored instance allocation, by allocating as
secondary node “noSecondary”.

Both allocate and relocate compute new node lists, whose score must be
ranked and the best option chosen. This means we can convert the code to
a generic function.

This patch implements allocate for two node requests. One node requests
can be done as soon as we have a valid allocateOn function for single
nodes.

This patch completes the implementation of hail relocate. It maps all
valid destination nodes through a ReplaceSecondary IMove, filters out
the failed relocations, computes the resulting scores and picks the
lowest one.

This patch implements a very stupid (and broken) version of hail
‘allocate’.

This patch removes the ktn/kti lists from most parts of the first half
of the loading sequence. Some remain as the [(String, Int)] is the
nicest way to lookup names and get indices back.

This removes the return of ktn/kti from Loader.mergeData and associated
functions.

This patch removes all uses of ktn/kti from the past-loader stages.

This is not yet used.

These will be used to remove even more uses of ktn/kti in non-critical
paths.

Since we have Node/Instance.name, we can now simplify a few constructs.

This strips the suffix from the objects themselves, not only from the
ktn/kti vars.

This patch makes the format of IAlloc.loadData be similar the same as
Loader.mergeData.

This patch moves the common loading sequence to CLI, such that hbal/hn1
and possible future scripts that take the input from same sources can
use it.

This moves the remaining loading function to Loader (together with its
associated support functions).

This patch generalizes a little the CLI handling by not passing in a
special function for help and such, but instead requiring that the
options object supports some common functionality.

Since both nodes and instances support some common functionality (names
and indices), we add a class so that we can access these attributes in a
generic way.

In order to simplify the data structures, we add back the name on the
node and instance objects. We still keep the index for, well, indexing,
but we will use the name directly from the object, in order to get rid
of the ktn/kti arguments which are passed around everywhere.

This new big patch does a couple of more cleanups in the loading of data
chapter:
  - introduce a Types module that holds most types (except the base
    Node/Instance/etc.) so that multiple other modules can use these
    (instead of only Cluster and its users)
  - bring IAlloc.hs in line with the recent changes of providing data
    types and not strings
  - removal of obsolete Utils.hs json-related functions