Add Apprise test button

[anthonylavado]

Description

Adds a route and UI button to send a test notification through Apprise. It will send a single message, with the same header as the regular notifications.

Fixes # (issue title here)
N/A

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce.
Please also list any relevant details for your test configuration

• Docker

In my test setup, Apprise is configured to post to Telegram.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have tested that my fix is effective or that my feature works

Changelog:

Include the details of changes made here

• Add testapprise route to server, and button on the Apprise config page

Logs

Here is a screenshot of the notification in action:

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[microtechno9000]

Nice work, will review

[microtechno9000]

looks good