Feat: allow saving the tab names in sessions

[griwes]

Requested feature

I would like Lualine to provide a way to save tab names in sessions. I do not believe this is currently possible; the PR that added tab renames (#574) briefly had this capability, but it appears that this has been removed. But without this capability, this feature is less usable than it should be.

Motivation

Tab names allow providing information as to what a tab represents. When this information is lost because it doesn't get saved in the session, one needs to remember exactly what the purpose of each tab originally was when restoring a session. Since it's Lualine that provides tab names, Lualine should also provide a way to persist them into sessions.

[tricktux]

Friendly bump of this issue 😄