(feat): Add function for filtering links before cache insertion

[mtekman]

Add function for filtering links before cache insertion:

For a given link type, include/exclude all links of that type
unless the paths optionally match case-sensitive strings.

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Motivation for this change

Before

My org-node graphs were cluttered with gmail links that I had no interest in.

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After

By specifying the custom setting

(setq org-roam-db-extra-links-type-filters '(
                                             ;; Excludes all telephone links
                                             ("tel" :exclude) 
                                             ;; Includes all https links except those matching "mail", "gitlab-static", etc.
                                             ("https" :exclude ("mail" "gitlab-static" "amazonaws"))
                                             ;; Excludes all http links except those matching "mail"
                                             ("http" :include ("mail"))))

This is much more manageable