Manifest Schema - Add provides

[N3X15]

Problem description

When forking a mod, it is imperative to change the identifier of the mod or tools like RimSort, RimPy, and (presumably) ModManager will get confused and select one of the mod directories with the same ID, often resulting in the wrong mod being loaded.

However, changing the mod identifier can also result in upstream mods that need to <loadAfter> the original mod freaking out because the mod they're looking for is not present.

Describe the solution

I propose adding a <provides> list to the manifest to signal to mod sorting tools that something is providing the interfaces that downstream mods need.

Alternatives

I haven't seen any alternative proposals that would address this problem.

However, one common-sense solution would just be to wait for all the downstream mods and rulesets to update their `. The issue with this solution is that it does not address stalled or abandoned mods that may take extended periods of time to update their references.

Additional materials

Forked mod:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Manifest>
    <identifier>EvolvedOrgansReduxForkedYetAgain</identifier>
    <version>2.0.1</version>
    <provides>
      <li>EvolvedOrgansRedux</li>
    </provides>
    <dependencies>
        <li>brrainz.harmony</li>
    </dependencies>
    <!--<incompatibleWith>
    </incompatibleWith>-->
    <!--<loadBefore>
    </loadBefore> -->
    <loadAfter>
        <li>brrainz.harmony</li>
    </loadAfter>
    <!--<suggests>
    </suggests> -->
    <showCrossPromotions>true</showCrossPromotions>
    <manifestUri>https://raw.githubusercontent.com/N3X15/EvolvedOrgansRedux/master/About/Manifest.xml</manifestUri>
    <downloadUri>https://github.com/N3X15/EvolvedOrgansRedux/releases</downloadUri>
</Manifest>