* tests based on jetty-runner do not work because
the jetty-runner JAR contains invalid Java SPI services config files
* due to these invalid files Jetty 11.0.20+ is unable to properly
initialize itself itself
* This change removes all tests based on jetty-runner
and bumps the Jetty version to 11.0.24
* There are already jobs using the Jetty Maven plugin to
launch a testing instance + run all tests
- set `ALLOW_PLANTUML_INCLUDE` only once and decentralized inside the `DiagramResponse` class and call this init method after initializing the server
- set `PLANTUML_SECURITY_PROFILE` to `INTERNET` by default (BREAKING CHANGES)
- add possibility to set PlantUML system properties over a file with `PLANTUML_PROPERTY_FILE`
- adjust documentation
- add "Breaking changes" hint to README
- revert the 4 missing tests, e.g. proxy test from commit 20468f5
- add virtual host name `test.localhost` to embedded jetty server
(JUnit Tests) since localhost and IP-Addresses are no longer
supported by the proxy and use this address inside proxy `src`
- add `test-localhost` support for the docker tests. To support
this the docker hostname need to be set to test.localhost by:
`--hostname=test.localhost` (only for the docker tests)
- proxy: add file format support for PDF
- proxy: add error messages on "bad request" response
- proxy: remove dead code
- old proxy: add error messages on "bad request" response
- fix incorrect README link to docs
- add `HTTP_PROXY_READ_TIMEOUT` option -- close#240
