Calendar component

[asvae]

In the scope of discussion we decided that:

• We want to have a small and simple calendar of our own. (using most popular features of existing solutions)
• And we may want to consider doing restyle in the course of feedback.

So, to implement this, we need:

• [ ] List of requirements
• [ ] Design (@xx13 )
• [ ] Implementation
• [ ] Docs
• [ ] Needs presentation from vuestic-admin (adding events)

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Previous issue:

Examples: https://vcalendar.io/attributes.html https://vuetifyjs.com/en/components/calendars/

Here's the ways I see we can handle this technically:

• Provide styling-wrapper component for v-calendar. That'll add support for vuestic colors and config. Pretty easy to do, very powerful. Con is external dependency (maybe also with significant bundle size - need to check).
• Implement limited component on our own. In many cases user is fine with pretty simple solution.

[m0ksem]

This PR should close https://github.com/epicmaxco/vuestic-ui/issues/1468 I think.

[LighthouseKeeperYN]

v-calendar dependency is pretty heavy: 180kb for calendar component alone.

[asvae]

I checked other UI frameworks and calendar implementations look rather rudimentary, so might be an a unique feature on our side if we manage to implement it.