Add a new make target that provisions dagger-ci declaratively

While at it, add help make target & make it the default.
This explains all make targets. Run `make help` to see it in action 😉

dagger-ci-pr1499-2022-01-26 API token was added as an AGE secret. It can
be accessed only by the intended recipients are able to decrypt it with
their private SSH keys.

    echo "TOKEN" | age -R .age.recipients.txt -o .do.dagger-ci-pr1499-2022-01-26.age

Do not assume that /bin/true exists on hosts running Docker.  Use "true"
and let the system resolve the path.

Re-enable all ssh Universe tests.

Signed-off-by: Gerhard Lazu <gerhard@lazu.co.uk>

.gitignore

@@ -31,3 +31,9 @@ docs/learn/tests/node_modules
 # Integration CI dagger.mod, dagger.sum
 dagger.mod
 dagger.sum
+
+# Local binaries
+bin/
+
+# Local environment variables
+.env