They are mostly intended to save space as the "new theme", if it
gets applied, takes up space like it's worth pure gold.
Paddings get made smaller on buttons, tabs and grids.
Also let the main tree receive a sane space padding.
Further fix the height of the top info panel (the one with the logo,
PVE version, login button ...).
Also the "start/stop/more/..." buttons from the tool bar above the
navigation tab bar gets fixed.
Login panel got also some small fixes together with all input
fields.
We use simple CSS overrides to achieve this all.
Working with the scss (sass) files and rebuilding the theme would
be nicer, but as I have no intend to start working with senchas
"build system" and we self have no sane way for compiling the sass
stuff also, this is the preferred way for now.
We add a new css stylesheet so that the current manager remains
untouched by this changes.
This makes the code more homogeneous and allows us to use the ExtJS
class autoloader in the future if we want (autoloader idea: ExtJS tries to load the
JS class file over HTTP based on the class name, no need to maintain a list
of includes)
