stringtables -> tab to space & AGMod to AGM

fixed some stringtable.xml files. Indentations, tabs, `Original` instead of `English`, and some stray `AGMod` to the default `AGM`

Why do some stringtables look like this:

    <Project ID="Arma3">
        <Package ID="AGM">
            <Container ID="AGM_Drag">

And others like this:

    <Project name="AGM">
        <Package name="Grenades">