hg: support protocol commands used by hg-evolve

When cloning or pulling from a repository which uses the evolve extension
Kallithea would require write permissions for multiple commands:
evoext_obshashrange_v1, _exttopics_heads and tns_heads.

https://foss.heptapod.net/mercurial/evolve/-/blob/6ffc4d7635fac0e605eb44b77de539f64c3739a2/hgext3rd/topic/server.py#L134
https://foss.heptapod.net/mercurial/evolve/-/blob/6ffc4d7635fac0e605eb44b77de539f64c3739a2/hgext3rd/evolve/obsdiscovery.py#L722

Fixed by adding them to the list of known read-only commands.