* Update install_log2ram.yml

Updated Ansible playbook to configure notification settings in Log2Ram...

The playbook incorrectly referenced 'MAIL=' - this should instead be 'NOTIFICATION='

Added support for customizable notification commands - 'NOTIFICATION_COMMAND='

* Update install_log2ram.yml

Aligned Ansible playbook settings with Log2Ram config defaults to ensure consistency and predictability.

* Update install_log2ram.yml

Added a task to install the prerequisite apt package 'gnupg'.

(GnuPG is required by the task, 'Add gpg key').

- Adds support for missing options in the /etc/log2ram.conf (USE_RSYNC and MAIL)
- apt-key command has been deprecated, as mentioned by issue #179. Changing it to use a keyring in /usr/share/keyrings

Use new trusted.gpg.d keyring for apt key, improve idempotency,
only update cache when necessary, only restart service when necessary.