Add support to update mounts - phase 1

[nfx]

trafficstars

• Return mountRemoteInfo from MountPoint#Mount
• Change signature of MountPoint#Source - expect Mount/Client as arguments, return mountRemoteInfo instead of mount source string
• remote acceptance tests for deprecated resources, that are otherwise making this feature more complicated
• all mounting clusters have to be re-created (or updated to DBR 10.2+) in case updateMount functionality is required.

Fix #513

[codecov[bot]]

Codecov Report

Merging #1029 (c8e2a88) into master (15181ad) will decrease coverage by 0.08%. The diff coverage is 95.23%.

@@            Coverage Diff             @@
##           master    #1029      +/-   ##
==========================================
- Coverage   90.73%   90.65%   -0.09%     
==========================================
  Files         108      108              
  Lines        9338     9391      +53     
==========================================
+ Hits         8473     8513      +40     
- Misses        513      520       +7     
- Partials      352      358       +6     

Impacted Files	Coverage Δ
storage/generic_mounts.go	95.16% <ø> (-2.42%)	:arrow_down:
storage/gs.go	94.87% <ø> (ø)
storage/s3.go	88.23% <ø> (ø)
storage/mounts.go	93.57% <95.00%> (-2.90%)	:arrow_down:
storage/resource_mount.go	95.34% <100.00%> (-4.66%)	:arrow_down:

[alexott]

I think that it makes sense to close this as mounts aren't recommended anyway