Improve installed.json handling in v2/tools

[MatteoPologruto]

Please check if the PR fulfills these requirements

• The PR has no duplicates (please search among the Pull Requests
  before creating one)
• Tests for the changes have been added (for bug fixes / features)

• What kind of change does this PR introduce?

Code enhancement

• What is the current behavior?

The installed.json is read everytime it needs to be updated and there is no mutex policy to prevent file corruption.

• What is the new behavior?

Information from installed.json is stored in a map and a mutex policy is introduced.

• Does this PR introduce a breaking change?

No

• Other information:

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 89.65517% with 3 lines in your changes missing coverage. Please review.

Project coverage is 20.70%. Comparing base (6287df1) to head (33f59b5).

Files	Patch %	Lines
v2/pkgs/tools.go	88.46%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #983      +/-   ##
==========================================
+ Coverage   20.01%   20.70%   +0.68%     
==========================================
  Files          42       42              
  Lines        2568     2565       -3     
==========================================
+ Hits          514      531      +17     
+ Misses       1968     1949      -19     
+ Partials       86       85       -1     

Flag	Coverage Δ
unit	20.70% <89.65%> (+0.68%)	⬆️

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[Xayton]

Before merging, we also need to add some code that, if the installed.json file is not parsable, it will delete it and retry, instead of panicking.

[MatteoPologruto]

Before merging, we also need to add some code that, if the installed.json file is not parsable, it will delete it and retry, instead of panicking.

This commit solves this issue. The installed.json is parsed only when the Tools struct is initialized and errors are ignored. If the json is corrupted, the installed map remains empty and any tool is downloaded from scratch, rewriting the installed.json file.