Stateless GET Parameter Support

[caronc]

Description:

Related issue (if applicable): n/a

GET parameters title, type, and format can be passed on the URL to provide default values if nothing in the message body exists (this is already how Stateful Apprise POSTs are handled). This is merely making both consistent.

Checklist

• [x] The code change is tested and works locally.
• [x] There is no commented out code in this PR.
• [x] No lint errors (use flake8)
• [x] Tests added

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (2b21ab7) 99.36% compared to head (1da364b) 99.36%.

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #166 +/- ## ======================================= Coverage 99.36% 99.36% ======================================= Files 7 7 Lines 785 791 +6 ======================================= + Hits 780 786 +6 Misses 5 5 ```

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