[horde] Finished importing horde FW_6 to packagist.org / composer / compatibility with newer PHP versions

[Lang, Ralf]

Hello,

Finally, all horde applications and libraries have been imported to the 
global composer repository, packagist.org

You can find the index here Packagist 
<https://packagist.org/packages/horde/>

Original code from the maintaina-com fork has been rebased on the 
current master branch. I imported the original tags from maintaina. 
These are alpha versions. I did not do anything about pear.
The only changes to master affect the composer.json file. I made it 
compatible with current versions of composer and packagist but I doubt 
anybody really used them in their previous state.

The "master" branch is generally left alone for those who need to run 
horde in its previous state based on PHP 7.2 - New development targets 
the FRAMEWORK_6_0 branch

Maintaina's FRAMEWORK_6_0 branch originally targeted PHP 7.4, 8.0 and 
8.1 and is known to work on these versions within reasonable limits of 
testing.

Active upstream support for PHP 8.1 has ended some weeks ago. Security 
fixes are available for the next 11 months.
I am currently working on full support for PHP 8.2 and 8.3.

I just finished the importing work. While the unit tests for almost all 
code has been ported to PHPUnit 9 and SHOULD work on the latest PHP, the 
CI pipelines are currently broken.
This is a high priority currently.

If you find any patch from master branch missing in FRAMEWORK_6_0, 
please create a PR or simply comment if you cannot create the patch 
yourself.

Regards

Ralf