* Added plaintext support to file_server browser
This commit is twofold: First it adds a new optional
field, `return_type`, to `browser` for setting the
default format of the returned index (html, json or plaintext).
This is used when the `Accept` header is set to `/*`.
Second, it adds a preliminary `text/plain`
support to the `file_server` browser that
returns a text representation of the file
system, when an `Accept: text/plain` header
is present, with the behavior discussed above.
* Added more details and better formatting to plaintext browser
* Replaced returnType conditions with a switch statement
* Simplify
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Co-authored-by: Matt Holt <mholt@users.noreply.github.com>
45132c5b24