Add ExecReload directive to chproxy service

[iamtalhaasghar]

so that systemd service can reloaded to fetch new changes from config file

Description

This will be helpful in reloading chproxy systemd service on the fly to reload changes from config file. Previously, it wasn't there and systemd relaod chproxy would say something like "you can not run 'reload' operation on this service".

Pull request type

Changes in documentation.

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

Checklist

• Linter passes correctly
• Add tests which fail without the change (if possible)
• All tests passing
• Extended the README / documentation, if necessary

Does this introduce a breaking change?

• Yes
• No

Further comments

nah, its just a simple change in documentation