Remove jquery.browser plugin

[sgiehl]

Description:

The jquery.browser plugin only had been used in a couple of places. Those checks were actually very old and meant for browser versions we already dropped support for.

Note: Vue.JS is only running on modern browsers anyway, and many of them are meanwhile based on Chromium (IE/Edge, Opera), Firefox or Safari.
The checks in the browser plugin would meanwhile be inaccurate and sometimes incorrect anyway.

Review

• Functional review done
• Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• Documentation added if needed
• Existing documentation updated if needed