Change packages metadata and rename tactics subfolder

[jneira]

• It changes author and copyright to The Haskell IDE Team as commented here
• It seems the maintainer should be an email: https://cabal.readthedocs.io/en/latest/cabal-package.html#pkg-field-maintainer, so i set @alanz one, not sure what can be set there
• I've set the category to Development, more appropiate and similar to other plugins
• If this it is accepted, will change the actual package metadata

... and i renamed the tactics folder to hls-tactics-plugin, to match the package name and to be consistent with the rest of plugins
//cc @isovector

[alanz]

Happy with the copyright changes, thanks.

Maybe we can ask the haskell foundation or org for an email address some time, its no big deal, mine is fine for now.

[Ailrun]

Actually I also wanted to change this. Thank you for the update!