Fix/popover performance

• Removes "v-tooltip"
• Adds a new "Popover" component

Some things have changed but it's similar:

• Does not render stuff until the popovers are activated, this makes a big difference in performance.
• Now you use slots "content" and "trigger" instead of "popover" and the rest.
• Less options but defaults that serve our needs well
• Didn't bother reimplementing that tiny arrow for tooltips
• Not as many alignment options, can be added if necessary. For example no 'bottom-end' so using just 'bottom'
• Only top and bottom alignment right now, no left/right for simplicity. We didn't have anything using them.
• Manual operation uses a close function passed as a slot parameter, and emits to tell parent component when popover is opened/closed.
• Doesn't attempt to move the popover when scrolling it out of view anymore, which makes it possible to read long posts through the preview even on mobile.
• You can now mouseover into the status preview without it disappearing, making it possible to click links and open profile inside the preview

Latest benchmarks for loading older statuses 4 times on timeline (time it takes to add the statuses and render the changes):

develop:

• 2.65s, 2.72s, 2.87s, 2.94s

fix/popover-performance:

• 0.76s, 0.74s, 0.79s, 0.93s

changed the description

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• 0723c075 - update changelog

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added 1 commit

• 813d121c - fix centering of certain dropdowns

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overall looks great.

most comments are nitpicks or just weird places.

i think i understand the reasoning for split x/y boundTo now at least, but feels like it needs even more comments quite often, at very least the props for new popover.

added 113 commits

• 813d121c...3ddf7ebe - 110 commits from branch develop
• 16302b56 - clean up and fixes, change popover padding -> margin
• 238afc4c - fix offset Y bug
• e7a793a9 - fix conflict

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added 1 commit

• 741c2b0d - make it easier to use status previews with hover

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mentioned in issue pleroma-meta#16 (closed)