[WIP] Notes on full reinstall

(without system compiler)

```
sudo apt install make
sudo apt install libc6-dev
sudo apt install python3-venv
sudo apt install zlib1g-dev
sudo apt install m4

sudo mkdir /opt/compiler-explorer
sudo chown user:user /opt/compiler-explorer

cd /opt/compiler-explorer
git clone https://github.com/compiler-explorer/infra
git clone https://github.com/compiler-explorer/compiler-explorer ce

cd infra
make ce
bin/ce_install install 'gcc 10.1.0'
bin/ce_install install 'clang 8.0.0'

export CC=/opt/compiler-explorer/gcc-10.1.0/bin/gcc
export CXX=/opt/compiler-explorer/gcc-10.1.0/bin/g++
export LD=/opt/compiler-explorer/gcc-10.1.0/bin/ld
export AR=/opt/compiler-explorer/gcc-10.1.0/bin/ar

update_compilers/install_binaries.sh

sudo ln -s /opt/compiler-explorer/gcc-10.1.0/bin/strip /usr/bin/strip
sudo ln -s /opt/compiler-explorer/gcc-10.1.0/bin/c++filt /usr/bin/c++filt

bin/ce_install install all the things!

bin/ce_install --enable nightly install 'gcc trunk'
```

TLDR takeaways: install_binaries depends on Clang 8, and most ce_install's depend on strip, which is part of gcc binutils

Also if you do `make ce` before python3-venv is installed, you need to do `make clean` first before being able to call `make ce` again

If something goes wrong during install_binaries, the folder for pahole will be empty and will not be built. You have to remove it every time before retrying install_binaries.

Gcc trunk is needed for readelf

You need c++filt for the unit tests

FPC needs AS to be in the path, so eventually it's unavoidable to install the system's gcc.