[feature] Poll web view

[tsmethurst]

Description

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If this is a documentation change, please briefly describe what you've changed and why.

This pull request adds a template + web view for rendering status polls in the frontend.

Produced HTML for a poll looks like this:

<figure class="poll">
	<figcaption class="poll-info">
		<span class="poll-expiry">Poll closed&nbsp;Aug 28, 2021, 10:40</span>
		<span class="total-votes">Total votes: 2</span>
	</figcaption>
	<ul class="poll-options">
		<li class="poll-option">
			<label aria-hidden="true" for="option-1" lang="en">50:50</label>
			<meter aria-hidden="true" id="option-1" min="0" max="100" value="0">0&#37;</meter>
			<div class="sr-only">Option 1:&nbsp;<span lang="en">50:50</span></div>
			<div class="poll-vote-summary">
				<span class="poll-vote-share">0&#37;</span>
				<span class="poll-vote-count">0 votes</span>
			</div>
		</li>
		<li class="poll-option">
			<label aria-hidden="true" for="option-2" lang="en">phone a friend</label>
			<meter aria-hidden="true" id="option-2" min="0" max="100" value="50">50&#37;</meter>
			<div class="sr-only">Option 2:&nbsp;<span lang="en">phone a friend</span></div>
			<div class="poll-vote-summary">
				<span class="poll-vote-share">50&#37;</span>
				<span class="poll-vote-count">1 vote</span>
			</div>
		</li>
		<li class="poll-option">
			<label aria-hidden="true" for="option-3" lang="en">ask the audience</label>
			<meter aria-hidden="true" id="option-3" min="0" max="100" value="50">50&#37;</meter>
			<div class="sr-only">Option 3:&nbsp;<span lang="en">ask the audience</span></div>
			<div class="poll-vote-summary">
				<span class="poll-vote-share">50&#37;</span>
				<span class="poll-vote-count">1 vote</span>
			</div>
		</li>
	</ul>
</figure>

And it's styled in the frontend like this:

Checklist

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If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

• I/we have read the GoToSocial contribution guidelines.
• I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
• I/we have performed a self-review of added code.
• I/we have written code that is legible and maintainable by others.
• I/we have commented the added code, particularly in hard-to-understand areas.
• I/we have made any necessary changes to documentation.
• I/we have added tests that cover new code.
• I/we have run tests and they pass locally with the changes.
• I/we have run go fmt ./... and golangci-lint run.

[NyaaaWhatsUpDoc]

looks good to me! squerge away!!