Log Message:
zabbix50: Update to 5.0.30

Changelog for 5.0.30:

New features:
  - Added JSONPath optimizations

Bug fixes:
  - Removed the ability to import a graph with an empty name and added graph
    name length validation up to 128 characters
  - Fixed the "i" icon alignment in the Info column in Problems \ 
section with
    compact view
  - Improved history syncer performance
  - Fixed vfs.fs.inode and vfs.fs.get to handle file systems with zero total
    inodes count
  - Fixed Zabbix JS (zabbix_js) crash when parsing short version of \ 
"timeout"
    option -t
  - Fixed script in OPSgenie media
  - Fixed spoofing X-Forwarded-For request header allows to access Frontend in
    maintenace mode

For details see https://www.zabbix.com/rn/rn5.0.30

And while here, also:
- Consolidate and deduplicate patches (move all of them into
  zabbix50-server/patches)
- Allow only one of the database to be selected (mysql or pgsql)
- Regenerate NetBSD-specific patch