Fixed a bug that caused the frontend-only mode to not work properly with telemetry enabled on the docker version

Removed demo server from multipleServer examples because people don't understand the concept of demo

* Add timestamp in result image

* Remove format on timestamp

* put code to insert and query data from database into separate file

* simplify obfuscation salt file handling

* use new DB interaction functions in telemetry.php

* use new DB interaction functions in stats.php

and fix indentation levels

* format telemetry settings file

* use new function for interacting with DB in index.php

* move drawing of the image into function and try to comment each section with what it does

* reorder lines for parts of the image to align with the order they appear on the image

* bugfix: display obfuscated and deobfuscated id in stats if id obfuscation is enabled

* improve error handling

* add missing PHPDocs to functions

* imageftbbox returns an array on success and false on failure so to check if the font is usable, check if we got an array

* fix dsn for postgres

* fix limit sql statement for postgresql

* remove obsolete require statement

* use require instead of require_once since the settings file might need to be loaded multiple times

because it just contains plain variables which will just get loaded into the current scope

* move require statements to the top of the file

* make sure files are readable before requiring them

* add constant to refer to the telemetry settings file and check if it is readable before loading it

* return null if no speedtest result was found for the given id and show according message to the user instead of just exiting

* use existing constant instead of string for telemetry settings file name

* uniformly use single quotes instead of double quotes as most code places already used single quotes

* somehow some tabs sneaked in, replace them to uniformly use spaces

* mysql now uses pdo, too, reflect that in the requirements documentation

* pass username and password as constructor parameters instead of via DSN

make the clickable area around the link to the privacy message a bit bigger again so that it's easier to click on mobile devices (#366)

* add missing line break

* fix privacy link being clickable over the full page width

* refactor getIP.php moving functionality into separate functions

* add some error checks

* remove closing php tags

* uniformly use single quotes for strings

most strings already used single quotes, some used double quotes

* refactor garbage moving functionality into functions

* fixes onend()

* Update speedtest.js

#318