Add initial support for page level annotations for product support

[Mpdreamz]

This adds product lifecycle annotations to the front matter yaml parser as requested in #95

Quick overview:

title: Elastic Docs v3
applies:
  stack: ga 8.1
  serverless: tech-preview
  hosted: beta 8.1.1
  eck: beta 3.0.2
  ece: unavailable

Its syntax is

 <product>: <lifecycle> [version]

Where version is optional.

all and empty string mean generally available for all active versions

applies:
  stack: 
  serverless: all

all and empty string can also be specified at a version level

applies:
  stack: beta all
  serverless: beta

Are equivalent, note all just means we won't be rendering the version portion in the html.

[colleenmcginnis]

@lcawl do you think ess should be hosted instead?

[Mpdreamz]

It should @colleenmcginnis I completely read over the fka in the new chart!

[bmorelli25]

I talked with @colleenmcginnis about this today. A couple thoughts:

1. The shorthand of option one is convenient but we worry that it might be confusing to new or irregular contributors. Option two is more verbose, but perhaps that is actually a good thing as theres a higher likelyhood that folks can see the frontmatter and understand the 1:1 correlation between frontmatter and the badges that appear at the top of a page.

2. The other topic we discussed relates to this excerpt from issue Add support for page-level metadata #95

At this moment, we are proposing that the page-level metadata uses the same deployment type, lifecycle, and version dimensions as described in #94. The assumption being that what is specified at the page-level is applicable to the entire page unless it's overridden by admonitions at the section, page, or line level.

You mentioned that this is a first step towards page level annotations so I imagine further functionality will come in later PRs. Just wanted to make sure you saw this.

[Mpdreamz]

Thanks @bmorelli25

I updated the syntax to:

title: Elastic Docs v3
applies:
  stack: ga 8.1
  serverless: tech-preview
  hosted: beta 8.1.1
  eck: beta 3.0.2
  ece: unavailable

Based on your conversation with @colleenmcginnis. More details are in the PR description.

[Mpdreamz]

This now also includes an initial html output for these front matter annotations: