update cert check validation

See merge request !6

update validator

See merge request !5

7911 - update appmonitor client

See merge request !4

Update appmonitor

See merge request !3

6621 update to php82

See merge request !2

update styling and docs

See merge request !1

The download client is part of the deployment script now.

server:
- allow single usage of a hash
- storing/ cleanup hashes
- prevent access to upper directories using "../"

client:
- added parameter "-l" to list items