Rewrite docker file so that:

- avoid k8s debian-base
- build h2load as statically as possible

libjemalloc1 package doesn't exist as it's now libjemalloc2 named

Get:1 http://security.debian.org/debian-security buster/updates InRelease [65.4 kB]
Get:2 http://deb.debian.org/debian buster InRelease [121 kB]
Get:3 http://deb.debian.org/debian buster-updates InRelease [51.9 kB]
Get:4 http://security.debian.org/debian-security buster/updates/main amd64 Packages [213 kB]
Get:5 http://deb.debian.org/debian buster/main amd64 Packages [7905 kB]
Get:6 http://deb.debian.org/debian buster-updates/main amd64 Packages [7868 B]
Fetched 8364 kB in 1s (6499 kB/s)
Reading package lists...
Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package libjemalloc1

fix reference to OpenSSL 1.1.1 branch

Cloning into 'openssl'...
warning: Could not find remote branch OpenSSL_1_1_1d-quic-draft-29 to clone.
fatal: Remote branch OpenSSL_1_1_1d-quic-draft-29 not found in upstream origin