Set license identifier according to upstream info

Apply patch to fix format string issue: https://github.com/hydrogen-music/hydrogen/issues/1739

Remove unnecessary quotes and curly braces.
Move to bash arrays with one entry per line.
Move cmake options to local bash array for better handling.
Adapt cmake calls to adhere to packaging guidelines.

Simplify quoting in file.

Drop upstreamed patch for fixing an install path.

Add liblo for new-session-manager support.
Add new-session-manager as optdepends.
Add patch for installing i18n files to the correct location (and upstreaming it).

Applying latest cmake packaging guidelines.
Simplifying use of pkgver.

Removing all (now not required) fixes and patches.
Moving all sodeps to package() and adding the respective packages
to makedepends. Minor cleanups.

Updating maintainer info. Adding all direct library dependencies. Adding upstream fixes for python scripts used during build time (to be python3 compatible). Simplifying cmake setup. Minor cleanups.

Upgrading to 1.0.0-beta1 (to finally use qt5). Removing all patches (most are not relevant anymore or are replacable by sed).
Dropping all doc related makedepends (docs submodule not included). Cleaning up pkgdir further, after stuff gets (still) installed to wrong locations.

Introducing rubberband back as optdepends. Cleaning up patches (replacing python2 patch with sed line).
Updating fix_desktop_file.patch to take care of FS#48801 (and opening upstream bug).
Installing hydrogen.svg also to hicolor-icon-theme dir. Opened bug about cleaning of data dir.

Adding all necessary patches to be able to build. Building html manual and tutorial and updating translations.
Adding various docs and cleaning up build.