DOCS-1206 - Another attempt to add API docs

[jpipkin1]

Purpose of this pull request

This pull request adds API articles for the following APIs:

• Parsers Library Management: https://api.sumologic.com/docs/#tag/parsersLibraryManagement
• Schema Base Management: https://api.sumologic.com/docs/#tag/schemaBaseManagement
• Source Template Management: https://api.sumologic.com/docs/#tag/sourceTemplateManagementExternal

This PR is the second attempt to add these articles. We reverted the previous PR #5940 to fix broken Algolia search.

Select the type of change

• Minor Changes - Typos, formatting, slight revisions
• Update Content - Revisions, updating sections
• New Content - New features, sections, pages, tutorials
• Site and Tools - .clabot, version updates, maintenance, dependencies, new packages for the site (Docusaurus, Gatsby, React, etc.)

Ticket (if applicable)

DOCS-1206