In addition to specifying the DB adapter explicitly via build tags,
allow bundling all available DB adapters to the binary (enabled via "all" tag).
The adapter may be chosen by setting `store_config.adapter_name` field in `tinode.conf`.

Modify build scripts and docker configs to support this.
Docker tinode-all image includes the bundled binaries, the adapter may be
chosen by providing ADAPTER_NAME env var.