Files and documentation could need some upgrade

[PlasmaHH]

It seems the documentation could need some information to reflect things that are not accurate anymore:

• git pull will not work since the submodule is in a detached head state. This can be fixed by co master before the pull ( which is not necessary for the first time anyways) or co of a recent tag name.

Additionally some things seem to have changed in the svd tools, also it should be mentioend that before running make one needs to "pip3 install --user svdtools" and then in the makefile the name of the tool is svd not svdtool ( or run "make SVDTOOLS=svd")

Last but not least for more convenience all the new versions could be checked in here, e.g. the STM32U5 is completely missing. This is especially useful as the current master "does not compile".