mosaic tile timeout

[philvarner]

1. Add a configuration timeout for the max allowed time that a mosaic tile can take to generate. This was set at 30 seconds (and still defaults to that) because the API Gateway has a max of 30 seconds of execution. However, this Lambda can be invoked directly via a Function URL or hooked up directly that way to a CloudFront URL, so the API Gateway limitation isn't a had limit now.
2. ake a few backports to the jinja init to allow it to work with the latest jinja version, which now throws an error with the latest code.
3. add 3.12 to testing matrix
4. prep for 0.14.0-1.0.5 release

[mbialas]

Looks good to me 👍