Add @tags metadata for filtering extensions

The option to filter by tag will be added to the extension repository page

Removing class only requires writing specific methods

Simply write it to the top level of the code, without wrapping the class

Miru-specific operations are performed only with Miru objects

For example, Miru.registerSetting

Add Miru.rawRequest method

Get Response header and will not automatically add baseUrl

Add Miru.storage related methods for persistent data storage

Add methods to read and write cookies

Show messages from extensions