[Feature] Check For Redundant Plugins

[mrfoxtalbot]

Inexperienced users often make the mistake of installing similar plugins whose feature overlap and even conflict.

Some examples are:

• Caching plugins.
• SEO plugins.
• Site Builders.

One way to prevent this would be to allow plugin authors to include a list of known incompatible plugins in their readme.txt file.

Site Health could pull that list from each active plugin on the site, compare it with the list plugins and show notices to let them users know that they probably do NOT want to have two SEO or caching plugins active at once.

[mrfoxtalbot]

To prevent abuse, we could require BOTH incompatible plugins to list each other in their readme.txt in order for Site Health to show this incompatibility.