Add InstallTool RPC method for PluginService

[Warashi]

What this PR does / why we need it:

With pipedv1's plugin architecture, we have to provide a way to install the tool used in the plugin.
I considered the following ways and propose the first way.

1. provide InstallTool RPC at the PluginService.
2. provide the directory path to the plugins in which the tool should be installed
3. provide nothing to the plugins, and the plugin does all of the installation, such as making the temp dir to install the tool, ...etc

I propose the first way because we should consider multiple plugins that want to install the same tool/version at the same time.
In such a situation, we should prevent race conditions, and we can handle this with a sync.Mutex or something similar in the first way.

Which issue(s) this PR fixes:

Part of #4980

Does this PR introduce a user-facing change?: No

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 22.82%. Comparing base (0e7a177) to head (c116f55).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5218   +/-   ##
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  Coverage   22.82%   22.82%           
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  Files         420      420           
  Lines       45309    45309           
=======================================
  Hits        10340    10340           
  Misses      34173    34173           
  Partials      796      796           

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[t-kikuc]

Only v1 is affected