[65] Added livenessProbe, readinessProbe and startupProbe optional to…

[aeciopires]

What this PR does / why we need it:

• Added optional livenessProbe, readinessProbe and startupProbe to all Zabbix components suggested by @leighwgordon in the issue #65
• Bump chart version
• Created example of readinessProbe to Zabbix-Server with two or more replicas in HA mode
• Created new optional values of livenessProbe, readinessProbe and startupProbe to all Zabbix components
• Updated documentation of chart

Special notes for your reviewer:

• This release don't has breaking changes

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• [x] DCO signed
• [x] Chart Version bumped
• [x] Variables are documented in the README.md

[aeciopires]

Hi @leighwgordon!

I implemented your suggestion in issue #65. Do you can test?