Make SeasonalMovingAverageModel and DeadlineMovingAverageModel to work with context

[Mr-Geekman]

Before submitting (must do checklist)

• Did you read the contribution guide?
• Did you update the docs? We use Numpy format for all the methods and classes.
• Did you write any new necessary tests?
• Did you update the CHANGELOG?

Proposed Changes

1. Look at Make SeasonalMovingAverageModel and children to work with context #905.
2. Look at Make DeadlineMovingAverageModel to work with context #907.

Closing issues

Closes #905.
Closes #907.

[github-actions]

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[codecov-commenter]

Codecov Report

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The diff coverage is n/a.

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