Checkpoint: front-haproxy serves some backend, but it still speaks directly to the backend, and shall use back-haproxy for backend intelligence.

2.4 implementes url normalization, needed on front facing part, see
https://cbonte.github.io/haproxy-dconv/2.4/configuration.html#4.2-http-request%20normalize-uri

IMS and MME are in the same instance, but there is only one TUN
per instance. IMS is not crucial right now so we temporarily remove it
until we implement a clean solution.

We were trying to patchelf a file that apparently exists when Theia
is compiled on Debian 8, 10 and 11, but not on Debian 9.

See merge request nexedi/slapos!1105

Include the hash of all parameters related to the embedded instance
as a comment in the standalone script, so that if the hash changes,
the script and its own hash change as well, and standalone service
will be restarted.

Generate standalone script in instance-theia.cfg.jinja.in instead of
in software.cfg, avoiding the need to forward all the parameters.

Include the hash of the relevant parameters in the abstract socket path,
so that when changing these instance parameters the promise waits until
the standalone service has taken the new parameters into account.

Change "Embedded Instance" to "embedded_instance", and rename existing
"Embdded Instance" into "embedded_instance" for compatibility.

Installing will setup git hooks, so we can do one step further and
also configure the mergetool

otherwise curl uses system ca-certificates if the system package is
installed and otherwise is not able to verify server certificates,
usually being observed in slapos as git refusing to clone with error:
SSL certificate problem: unable to get local issuer certificate

See merge request nexedi/slapos!1103

On Debian 9, the given rpath seem to be ignored when compiling
the `keytar` dependency of theia, for unknown reasons.

- Move [theia] section and dependencies into component/theia
- Make [theia] section shared

This was missing in this software and in 03c5b311 (Stop using
hexagonit.recipe.download, 2021-12-03) the hash got out of sync

also mention automatic installation method