Clean up and fix consistency issues in buildscripts

[IThundxr]

Changes:

• Switch to double quotes everywhere instead of single quotes
• Use newer dependency format in common buildscript
• Remove unused maven
• Use fabric mixin in common
• Don't specify names for mavens
• Configure all Jar tasks to include LICENSE

Requires #122 to be merged first

[jaredlll08]

There were a few parts of this PR that I wasn't a fan of, and unfortunately too intertwined with the previous PRs, so I've split the single commit up into multiple so that they can be merged.

Switch to double quotes everywhere instead of single quotes

I've actually swapped everything to use single quotes unless it involves string interpolation. double quoted strings are Groovy Strings, which have an overhead for parsing, whereas single quoted strings are just raw Java strings.

Don't specify names for mavens

I mentioned on discord that I know these were used but I didn't know where. I have since found out.
If an artifact can't be found, it lists the name of the maven, for example, changing the Fabric repository url to https://maven.example.com and refreshing the project, prints out:

Plugin [id: 'net.fabricmc.fabric-loom', version: '1.15.5', apply: false] was not found in any of the following sources:

- Plugin Repositories (could not resolve plugin artifact 'net.fabricmc.fabric-loom:net.fabricmc.fabric-loom.gradle.plugin:1.15.5')
  Searched in the following repositories:
    Fabric(https://maven.example.com)

if we remove the name though, we get

Plugin [id: 'net.fabricmc.fabric-loom', version: '1.15.5', apply: false] was not found in any of the following sources:

- Plugin Repositories (could not resolve plugin artifact 'net.fabricmc.fabric-loom:net.fabricmc.fabric-loom.gradle.plugin:1.15.5')
  Searched in the following repositories:
    maven(https://maven.example.com)

Obviously with most mavens it will be clear what it actually is, like if the Fabric maven went down and a user got maven(https://maven.fabricm.net), I'm sure they will be able to figure out that maven.fabricmc.net is the Fabric maven...

In general though I think including the name is good practice.

Remove unused maven

I don't think we need to list the fabric maven there, at-least I can build without it just fine