URL encode remote emoji pack names (#362)

[akkoma] / test / instance_static / emoji / test with spaces / pack.json

{
    "files": {
        "blank": "blank.png",
        "blank2": "blank2.png"
    },
    "pack": {
        "description": "Test description",
        "homepage": "https://pleroma.social",
        "license": "Test license",
        "share-files": true
    }
}