Merge branch 'rnou/thallium_support' into 'master'

Migration to full Thallium

This MR migrates to Thallium removing the Hermes dependency.
- Increased performance
We also included some optimizations:
- DIRENTS compression
- SFIND optimization and server-side computing --server-side (still sends the list of files, can be further optimized with -C)
- INLINE DATA (i.e, 4KB) to the database (rocksdb) for small files
- READ PREFETCH of the inline data on open
- WRITE optimization for small files (from 3RPC to 1RPC)
- DIRENTS pagination and retry
New :
- Some of the variables that are available on the config.hpp are also available as environment variables. 
- New tests to increase coverage
- New 0.9.6 dependencies (to cover thallium)

See merge request !273