Add YAML config schema for auto complete support

[cbos]

Description

Editor support auto complete for yaml files if there is a schema.
I created the schema and updated the tips and tricks page to others can use it as well.

NOTE: the described url does not work until it is merged, but you can use https://raw.githubusercontent.com/cbos/homer/config_schema/.schema/config-schema.json in the meantime to test auto complete

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• I've read & comply with the contributing guidelines
• I have tested my code for new features & regressions on both mobile & desktop devices, using the latest version of major browsers.
• I have made corresponding changes to the documentation (README.md).
• I've checked my modifications for any breaking changes, especially in the config.yml file

[bastienwirtz]

I love this! Thanks @cbos 🙏
I'll will take some time to look at it in details soon.

[cbos]

As soon as the PR is merged, it can be registered at https://www.schemastore.org/json/
Once that is done, it will be available to all editors supporting schemas for YAML
I can create a PR for that.
https://github.com/SchemaStore/schemastore/blob/master/CONTRIBUTING.md#how-to-add-a-json-schema-thats-self-hostedremoteexternal

It will be just a reference to the schema hosted in this repo, so as soon as that is updated, it will be available.

[bastienwirtz]

Awesome work @cbos, thanks a lot!
A few details but it looks good

[cbos]

@bastienwirtz
I have reworked the file based on your comments.
Footer can be a boolean or a String now.

[cbos]

@bastienwirtz
Thanks for merging the PR.
I have created a PR for the schemastore as well: SchemaStore/schemastore#4579
Once that is merged, the support in the editors will be even more available.