Add editmeta by request to REST

[spacehamster87]

Current State

• Job Metadata can be modified by REST API but only by knowing the Database ID of the job
• This is often not known to external systems, e.g. Slurm Nodes or similar

This Change

• Adds REST API Function to update/add meta_data to job by Request
• Job identified by: Slurm-ID, Clustername, and Starttime

Important / Breaking

• HTTP-Request Method PATCH is now used exclusively by existing editMeta function/endpoint
• HTTP-Request Metod PATCH is used exclusively by new editMetaByRequest function/endpoint

[spacehamster87]

Opened as draft to collect feedback first.

Addition was made necessary by local request to add meta_data information sourced from remote systems.

[spacehamster87]

Outdated Branch / PR Contents (500+ Commits) -> Migrated changes manually to current state, see #496