[Roam] import settings/feature requests

[dropcase]

Hi, I'm working on importing my Roam graph (~7200 notes) and looking for a few updates to help with the migration.

• Option to replace "invalid" characters in file names with a default (or user-choice option), possibly with adding the original naming as the title value in YAML frontmatter
• Option for removing one level of indented bullets, tested as working with this sed string: s/ \* /* /g
• Option for removing bullets from headers, using these for H3 and H2 as an example: s/\* ###/###/g and s/\* ##/##/g
• Option to use the create-time and edit-time from the Roam JSON Schema in YAML frontmatter as created and updated dates

I'll share updates if I'm able to test anything on my local system. Thanks!