Boatload of header cleanup

See merge request !14

OK, so you go through a bunch of steps and come to these instructions:

> There should now be a CiviCRM link in your Drupal menu.  Click that link and
> the CiviCRM Menu, Shortcuts, Search and New Individual Blocks should appear.
> You can now explore CiviCRM end-user features and begin configuring CiviCRM
> for your site/organization needs.

This should be the end of the installation guide. But, if you skim the TOC,
it keeps on going!

I *think* what's going on here is that people wanted to add some sections
which are sort of independent of the main flow of installation.

These probably should be moved/referenced in some other way, but I don't
really want to think too hard.  This commit just mitigates the confusion
a bit by setting the subsequent sections (re:MySQL encryption and troubleshooting)
under the heading "Addenda".

When the first heading of the document says...

> "Scope of this guide and alternative installation methods"

It breaks my English parser, and I start to cry. Just a little. On the inside.

1. Use sentence-case.

2. There will have been less of the future-past-perfect.

3. Conjugate actively.

1. Use sentence-case per style-guide (all files)
2. Don't need to explain every detail in the title (WP file)

1. Title is more specific/wordy than it needs to be.

2. Capitalizing the page title ("Configuration Checklist") is correct,
   but (as a reader skimming) it *looks* wrong because it doesn't match
   the norm and it lacks anything (quotes/italics/bold) to set it aside.

Just use a plain noun instead of a proper noun.

1. Resources in redundant.
2. The other section headings have active verb-phrase. This is a little closer.
3. The dash in "Trouble-shooting" is inconsistent. It's not wrong per se, but
   it's a little unusual, and it should be consistent with the title of
   liked page.

1. Use sentence-case

2. Don't be so wordy.  The paragraph explains this stuff - you don't need
to put the whole explanation into the TOC.

Before:

* Each CMS chapter uses slightly different headings and anchors
  for the same conceptual steps.
* Several of them try to distinguish when you do/do-not need translations,
  but they're arbitrarily different.

After:

* Each CMS chapter uses the same headings and anchors.
* If there was a different anchor before, then that anchor is still valid (but it is no
  longer visible or primary).
* It still tries to distinguish when you do/do-not need translations, but
  the language is simpler and more consistent.

Add install docs for drupal 9 now that the demo site shows it works

See merge request !8

Normalize line-endings

See merge request !13

This repo currently has 16 markdown files, of which 8 have `CR` endings and
8 have `CR-LF` endings.  For comparison, the dev-docs and sysadmin-guide
have strictly `CR` endings.

Add info about installing sample data in drupal 8

See merge request !11

Update docs/drupal8/index.md - small syntax fix

See merge request !10

TLS with MySQL

See merge request !7

Add details on allowing patching based on dependencies

See merge request !6

Update referene from 5.21 ESR to be 5.27 ESR and bump minimum MySQL version information

See merge request !5

Add note about pear/exception conflict resolution

See merge request !4