chain commands, and let a project refine a catalogue stack

myos build up logs host/fabio runs the three in order and stops at the first
failure, the way make build up logs STACK=host/fabio did. Leading words that
name commands are commands; the first word that is not one starts the stacks.

A stack found in several directories of the stack path is now merged rather
than shadowed, least specific first, so a project drops
stack/postgres/postgres.local.yml next to the catalogue's postgres.yml and
refines it. Settings hooks follow the same order, so a project can redefine a
default the catalogue ships. Neither engine did this before: the project
directory simply hid the catalogue one.

An unknown command now says so and suggests the command to type, instead of
printing the whole usage.

spec/golden/expected.cli/cat-unknown-target.txt

@@ -1,28 +1,3 @@
 ERROR: unknown command: doesnotexist
-Usage: myos [options] <command> [stack...] [VAR=value...] [-- args...]
-
-Options:
- -C DIR work in DIR instead of the current directory
- -e ENV environment (default: local, or ENV from the config)
- -H HOSTS run on remote hosts instead (comma separated, or "all")
- -n, --dry-run print the commands instead of running them
- --color WHEN always, never or auto (default: colour when on a terminal)
- -v, --verbose show what myos does
- -d, --debug show every command
- -h, --help this help
-
-Commands:
- up down start stop restart recreate manage the containers of a stack
- ps logs config exec run inspect and enter them
- ls [--groups] list the stacks myos can see
- env [VAR...] show resolved variables
- env-update fill .env from the .env.dist templates
- doctor check the installation
- version print the myos version
-
-Stacks:
- myos up the stack of the current directory
- myos up host a group, expanded from host=... in a .env or .mk
- myos up host/fabio a single stack
- myos up postgres:9.6 a versioned stack
+ERROR: to act on a stack of that name, say what to do: myos up doesnotexist
 [exit 2]

spec/golden/expected.cli/chain-build-up-logs.txt

@@ -0,0 +1,6 @@
+docker compose -f @WD@/stack/host/fabio.yml -f @MYOS@/share/compose/networks.yml -p testhost --project-directory @WD@/stack/host build
+docker network create tester-local
+docker network create testhost
+docker compose -f @WD@/stack/host/fabio.yml -f @MYOS@/share/compose/networks.yml -p testhost --project-directory @WD@/stack/host up -d
+docker compose -f @WD@/stack/host/fabio.yml -f @MYOS@/share/compose/networks.yml -p testhost --project-directory @WD@/stack/host logs --follow --tail=100
+[exit 0]

spec/golden/expected.cli/chain-print-two.txt

@@ -0,0 +1,5 @@
+COMPOSE_PROJECT_NAME testhost
+APP consul
+COMPOSE_PROJECT_NAME testhost
+APP consul
+[exit 0]

spec/golden/expected.cli/chain-up-group.txt

@@ -0,0 +1,5 @@
+docker network create tester-local
+docker network create testhost
+docker compose -f @WD@/stack/host/consul.yml -f @WD@/stack/host/fabio.yml -f @WD@/stack/host/registrator.yml -f @MYOS@/share/compose/networks.yml -p testhost --project-directory @WD@/stack/host up -d
+docker compose -f @WD@/stack/host/consul.yml -f @WD@/stack/host/fabio.yml -f @WD@/stack/host/registrator.yml -f @MYOS@/share/compose/networks.yml -p testhost --project-directory @WD@/stack/host ps
+[exit 0]

spec/golden/expected.cli/host-target.txt

@@ -1,2 +1,3 @@
-ERROR: no stack given, and no compose file in @WD@
+ERROR: unknown command: host
+ERROR: to act on a stack of that name, say what to do: myos up host
 [exit 2]