Permit to change the forcesave options with env variables

[ppom0]

I recently had a loss of data due to OnlyOffice not detecting end of editing sessions and not saving back documents.

I discovered the forcesave autoAssembly option, which is very valuable to me.
But I had trouble overriding local.json in a working manner:
If I mount it to the container, it gets overrode by the entrypoint, and if I mount it read-only, the entrypoint crashes.

So I patched the container entrypoint, to be able to configure those parameters as environment variables.

Tell me what you think about this PR and which changes you'd need to merge it.

Many thanks!

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

Paco seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[thopico]

Hello !
Thanks a lot @aopom for this PR, I faced similar issue and lost also lot of work...

Any idea when the dev team will have time to review this PR?
It is quite simple and would help many of us (thinking about issues nextcloud/documentserver_community#12 nextcloud/documentserver_community#77 nextcloud/documentserver_community#78 nextcloud/documentserver_community#87 nextcloud/documentserver_community#100)

Thank you