Session management updates

[surbhiia]

This PR covers the following:

• Starting the first session on application start (as soon as ServiceManagerImpl is loaded), resolving First session is not created on application start #781
• Adding two separate configs for session foreground and background timeout, resolving Same session timeout config value used for foreground & background #794
• Adding a no-op session manager as default in InstallationContext API, interim resolution of [Discuss] SessionManager argument in InstallationContext API #795
• Renaming SessionIdTimeoutHandler to SessionBackgroundTimeoutHandler, part of Refactoring proposals for session related code #793

[LikeTheSalad]

Hi @surbhiia

Thank you for these changes. There's one that I think we need to review if it's needed:

Adding two separate configs for session foreground and background timeout, resolving #794

We discussed in the last SIG meeting that it's probably not a good idea to have different behaviors based on whether the app is in the "foreground" or "background", because those terms might mean different things depending on the app. For example, if an audio streaming app is "backgrounded", but the audio is still playing, probably its developers would want the same "foreground-behavior" of OTel to be running. So, in general, it's best not to depend on "app states" to define different behaviors, because we cannot guarantee that those would mean the same for all apps. So regarding this particular feature, it seems like it's better if we just define one timeout that's always present, regardless of the app state.

Please let me know if I missed something, @breedx-splk @bidetofevil