Allow adding extra fields

[mosheavni]

Closes #31
Allows to add extra fields to the auto discover and the standard configs without having to copy the entire block.
Also some markdown linting.

[Doron-Bargo]

Hi @mosheavni - thanks for your contribution
Please let us know when you finish with your PR so we can review it

[mosheavni]

sure @Doron-Bargo I'm done now.
Tested with these:

helm template -s templates/configmap.yaml --set configType="custom" .
helm template -s templates/configmap.yaml --set configType="custom" --set-file filebeatConfig.customConfig=/tmp/filebeat.yaml .
helm template -s templates/configmap.yaml --set configType="standard"
helm template -s templates/configmap.yaml --set configType="autodiscover"

All of these generates a valid filebeat.yml in the configmap.

[mosheavni]

@mirii1994 @Doron-Bargo
I added another value for any custom processor to add to the default configs.

[mirii1994]

Hi @mosheavni thanks for your contribution! I'll review your PR in the next couple of days :)

[mosheavni]

@mirii1994 @Doron-Bargo anything?

[mirii1994]

Hi @mosheavni great work!! :)
I commented out environment & foo in values.yaml extraFields, so that they would use an examples, bumped the chart's version, and edited some of the readme.
Please undo the linting in the README.md file.

[mosheavni]

thanks @mirii1994
the README changes are an important part of the PR. Can you still review it? if you need specific changes, I'll gladly add them.
Thanks again :)

[mirii1994]

@mosheavni please undo the linting on the README.md file, so that I can review it :)

[mosheavni]

@mosheavni please undo the linting on the README.md file, so that I can review it :)

there was no linting made, only necessary relevant changes that reflects the changes of the code.