Dependencies not in order

[justanwar]

Following stack_wallet/blob/staging/docs/building.md sequentially will cause user to encounter errors as some things in the earlier sections require dependencies that are only installed in the later sections.

Some examples:

justanwar@stack-2004:~$ flutter precache
Error: Unable to find git in your PATH.

(requires git which will be installed at Install basic dependencies)

justanwar@stack-2004:~$ sudo apt-get install -y vapigen
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package vapigen

justanwar@stack-2004:~$ pip3 install --upgrade meson==0.64.1 markdown==3.4.1 markupsafe==2.1.1 jinja2==3.1.2 pygments==2.13.0 toml==0.10.2 typogrify==2.0.7 tomli==2.0.1

Command 'pip3' not found, but can be installed with:

sudo apt install python3-pip

(requires python3-pip, which is only installed at Linux desktop specific dependencies)