Add optional auto-creation of parent dirs for keystore path in LetsEncrypt helpers

[SteveOberst]

Introduces a new boolean property lets-encrypt-helper.auto-create-keystore-dir that controls whether the helper will automatically create missing parent directories for the configured keystore path.

Changes

• TomcatWellKnownLetsEncryptChallengeEndpointConfig

  • Added support for auto-creating parent directories before attempting keystore creation.
  • Throws IllegalStateException if the parent directory does not exist and auto-create is disabled.

• JettyWellKnownLetsEncryptChallengeEndpointConfig

  • Applied the same changes for consistency.

• Documentation

  • Extended the configuration table with the new property.

• Tests

  • Added JUnit tests verifying both enabled (dirs are created) and disabled (fails fast) behavior.

New property

lets-encrypt-helper.auto-create-keystore-dir=true   # default

Motivation

Previously, the helper would fail with a vague error if the keystore path’s parent directories didn’t exist.
This change makes setup smoother for most cases, while still giving operators the option to disable auto-creation if they prefer strict configuration management.