Add Viewer support

[forsyth2]

Issue resolution

• Closes [Feature]: Create HTML page for global time series #601. Follow-up to Create global time series Viewers #616.
• Corresponding zppy-interfaces PR: Add Viewer support zppy-interfaces#9

Select one: This pull request is...

• a bug fix: increment the patch version
• a small improvement: increment the minor version
• an incompatible (non-backwards compatible) API change: increment the major version

1. Does this do what we want it to do?

Objectives:

• Objective 1
• Objective 2
• ...
• Objective n

Required:

• Product Management: I have confirmed with the stakeholders that the objectives above are correct and complete.
• Testing: I have added or modified at least one "min-case" configuration file to test this change. Every objective above is represented in at least one cfg.
• Testing: I have considered likely and/or severe edge cases and have included them in testing.

If applicable:

• Testing: this pull request introduces an important feature or bug fix that we must test often. I have updated the weekly-test configuration files, not just a "min-case" one.
• Testing: this pull request adds at least one new possible parameter to the cfg. I have tested using this parameter with and without any other parameter that may interact with it.

2. Are the implementation details accurate & efficient?

Required:

• Logic: I have visually inspected the entire pull request myself.
• Logic: I have left GitHub comments highlighting important pieces of code logic. I have had these code blocks reviewed by at least one other team member.

If applicable:

• Dependencies: This pull request introduces a new dependency. I have discussed this requirement with at least one other team member. The dependency is noted in zppy/conda, not just an import statement.

3. Is this well documented?

Required:

• Documentation: by looking at the docs, a new user could easily understand the functionality introduced by this pull request.

4. Is this code clean?

Required:

• Readability: The code is as simple as possible and well-commented, such that a new team member could understand what's happening.
• Pre-commit checks: All the pre-commits checks have passed.

If applicable:

• Software architecture: I have discussed relevant trade-offs in design decisions with at least one other team member. It is unlikely that this pull request will increase tech debt.