Merge pull request #897 from uptane/feat/support-external-ed25519-sigs

Support adding external ed25519 signatures

v3.2.10

98% of this is just library updates.
The remaining 2% consists of updates to the v2 package-search api to allow
filtering packages by a list of filenames

v3.2.9

98% of this is just library updates.
The remaining 2% consists of updates to the v2 package-search api to allow
filtering packages by a list of filenames