helm/fluentbit K8S-Logging.Exclude & and Mem_Buf_Limit toggle

[marcosartori]

What this PR does / why we need it:
Adds the ability to set K8S-Logging.Exclude for stopping logs getting to loki (default Off like it is now)
Adds the ability to set Mem_Buf_Limit to any value you want (default 5MB)

Which issue(s) this PR fixes:
n/a its something that I need and figure others might want this

Special notes for your reviewer:
when I run make helm and deplyo fluent-bit this (not my change)

batchSize: 1048576

gets converted and then prevents starting (so I quoted it locally and built the chart to make it work, didn't add that to the pr though, however I pretty sure its not correct so can fix at same time by quoting if you guys wish)

I think I catered for everything I used vim to edit as my vscode linter was basically changing everything, so would be great to know what one is used here so I can follow.

I updated the readme, I have deployed to a k3d cluster and looked good

loki-promtail-j4shw          1/1     Running   0          24m
loki-promtail-mr7p7          1/1     Running   0          24m
loki-0                       1/1     Running   0          24m
loki-fluent-bit-loki-hp2wt   1/1     Running   0          23m
loki-fluent-bit-loki-dfbm2   1/1     Running   0          23m

Checklist

• Documentation added
• Tests updated

[CLAassistant]

All committers have signed the CLA.

[cyriltovena]

LGTM. and yes I'd like that PR to fix the quote of batch size ✌️