Site Template Customizations Documentation

[joshdentremont]

Purpose / why

Adding information about customizing your site template sites

What changes were made?

Added a new page with some empty sections that need to be filled in. Some of these are issues that were identified here: https://github.com/Islandora/documentation/issues/2286

Verification

These sections should be filled in then tested

Interested Parties

• @Islandora/documentation
• @Islandora/committers

Checklist

Pull-request Reviewer

Pull-request reviewer should ensure the following:

• [ ] Does this PR link to related issues?
• [ ] Does the proposed documentation align with the Islandora Documentation Style Guide?
• [ ] Are the changes accurate, useful, free of typos, etc?

Person Merging

The person merging should ensure the following:

• [ ] Does mkdocs still build successfully? (This is indicated by TravisCI passing. To test locally, and see warnings, see How To Build Documentation.)
• [ ] If pages are renamed or removed, have all internal links to those pages been fixed?
• [ ] If pages are added, have they been linked to or placed in the menu?
• [ ] Did the PR receive at least one approval from a committer, and all issues raised have been addressed?