bookmarks: add support for log-like template keywords and functions This is basically the same as 5d9b765dbe15 "tags: unblock log-like template keywords and functions."

fix: add progress bar for number of file revisions processed This ensures responsiveness when the configured tools are slow or numerous. Differential Revision: https://phab.mercurial-scm.org/D3848

fix: use a worker pool to parallelize running tools This is important for usability when tools are slow or numerous. Differential Revision: https://phab.mercurial-scm.org/D3846