Added configuration to enable/disable achievement system

[dastgirp]

Pull Request Prelude

• I have followed proper Hercules code styling.
• I have read and understood the contribution guidelines before making this PR.
• I am aware that this PR will be closed if the above-mentioned criteria are not fulfilled.

Changes Proposed

Configuration to enable/disable achievement system database loading and validation.

Affected Branches:

Issues addressed:

Known Issues and TODO List

[HerculesWSAPI]

This change is 

[kyeme]

I disable the system and try to login I got this error and map crashed.

[dastgirp]

Ah, it seems more checks are needed in case the user already have achievement

[HezekiahZratinel]

im getting that error too.. and i also try to create a new account and this error shows up and the server automatically restart on its own..

[shadow-mo0n]

Still getting an map crash..

[4144]

look like you have already assigned achievements in sql db. but hercules not read achievements from configuration files. from here many errors in console.
crash probably because missing init code

[shadow-mo0n]

Im not actually using this Achievement System. I added this code in my server to disable the system. Also my achievements_db is on default.
I think the check in libconfig files is causing the crash. It should be always be loaded even if you set the feature_enable_achievement to false.