docs: Update the user guide (DEV-1049)

[flavens]

resolves DEV-1049

[flavens]

@mdelez I may have missed some things. Please, let me know!

[mdelez]

your changes look good :)

I found some small things to change:

/user-guide/project

selecet -> select

since the example uses english, I think the labels in the resource of this image should be in english as well

something is wrong with the formatting here

/user-guide/system

has no more -> no longer has

/user-guide/data

the smaller will be the resource viewer for each -> the smaller the resource viewer for each will be

some general notes

• We seem to be sticking with American english so all occurrences of "centre" should change to "center"
• I would advise against adding "Not yet implemented" notes in the docs because there's no telling when those features will be implemented and it looks a bit bad if it stays in the docs for years.

[flavens]

@mdelez concerning the screenshot with the classes Buch/Buchseite, my user account is in English and we always get the label in German (why?!) so I cannot change it now.

[mdelez]

@mdelez concerning the screenshot with the classes Buch/Buchseite, my user account is in English and we always get the label in German (why?!) so I cannot change it now.

hmm strange...is there an english label? Otherwise you could just make the resource again just for the screenshot. It's not a big issue but consistency is nice :)

[flavens]

@mdelez concerning the screenshot with the classes Buch/Buchseite, my user account is in English and we always get the label in German (why?!) so I cannot change it now.

hmm strange...is there an english label? Otherwise you could just make the resource again just for the screenshot. It's not a big issue but consistency is nice :)

The thing is: even when we have English and German labels, the German one is displayed by default. Like the list label order issue, you fixed... Should I report it? I did a test locally and German labels out!