Add UUID prefix to new notes

[lambtho12]

Proposed change

This allows the user to specify if they want an UUID prefix in the filename of the new notes (falseby default).
Two types of prefixes are supported:

• rand: a random 6-char string
• <input for os.date()> such as %Y%m%d%H%M(default)

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Code quality improvements to existing code or addition of tests
• Documentation update

Additional information

• Related to discussion Separating title from file name #56

Checklist

• I am running the latest version of the plugin.
• The code change is tested and works locally.
• There is no commented out code in this PR.
• The code has been formatted using Stylua (a .stylua.toml file is provided)
• The code has been checked with luacheck (a .luacheckrc file is provided)
• The README.md has been updated according to this change.
• The doc/telekasten.txt helpfile has been updated according to this change.

[lambtho12]

Stylua failed because of a HTML 403 issue... not sure what is the problem. Anyway, this should be ok to merge @renerocksai

[renerocksai]

Sorry for taking so long. Will merge now.