UTBot Java architecture - first version. (#1403)

UTBot Java overall architecture - fist version.

Author: korifey

docs/OverallArchitecture.md

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+# Overall Unit Test Bot Architecture
+
+Unit Test Bot overall architecture can be presented as following bird-eye view. Look below to check each component's purpose.
+
+```mermaid
+flowchart TB
+    subgraph Clients
+        direction LR
+        IntellijPlugin        
+        MavenPlugin["Maven/Gradle plugins"]
+        GithubAction-->MavenPlugin
+        ExternalJavaClient[\External Java Client\]
+        CLI
+        ContestEstimator    
+                     
+    end    
+
+    subgraph Facades
+        direction LR
+        EngineMain[[EngineMain]]
+        UtBotJavaApi[[UtBotJavaApi]]
+        GenerateTestsAndSarifReport[[GenerateTestsAndSarifReport]]       
+    end
+    IntellijPlugin--RD-->EngineMain
+    MavenPlugin-->GenerateTestsAndSarifReport
+    ExternalJavaClient-->UtBotJavaApi
+
+    subgraph API["Generation API"]
+        direction LR
+        TestCaseGenerator[[TestCaseGenerator]]
+        CodeGenerator[[CodeGenerator]]
+    end
+    Facades-->API
+    CLI-->API
+    ContestEstimator-->API
+    
+        
+
+    subgraph Components
+        direction LR
+        SymbolicEngine-->jlearch
+        SymbolicEngine-->ConcreteExecutor
+        Fuzzer-->ConcreteExecutor
+        SarifReport
+        Minimizer
+        CodeRenderer
+        Summaries
+        jlearch
+    end    
+    CodeGenerator-->CodeRenderer
+    TestCaseGenerator-->SymbolicEngine
+    TestCaseGenerator-->Fuzzer
+    TestCaseGenerator-->Minimizer
+    TestCaseGenerator-->Summaries
+    GenerateTestsAndSarifReport-->SarifReport
+
+    UTSettings((UTSettings))
+    UTSettings<--RD/local-->Components    
+    UTSettings<---->Clients
+    TestCaseGenerator--warmup-->ConcreteExecutor
+    ConcreteExecutor--RD-->InstrumentedProcess
+
+```
+
+## Typical interraction between components 
+
+Interaction diagram started from Intellij plugin UI is presented below
+```mermaid
+sequenceDiagram
+    autonumber
+    actor user as User
+    participant ij as Intellij plugin
+    participant engine as Engine process
+    participant concrete as Instrumented process
+    
+    user ->> ij: Invoke "Generate tests with UTBot"
+    ij ->> ij: Calculate methods, framework to show
+    ij ->> user: Show UI
+
+    break user clicked "Cancel"
+        user -->> user: Exit
+    end
+    user ->> ij: Click "Generate tests"
+    ij ->> ij: Calculate what jar need to be installed
+        
+    opt Some jars need to be installed  
+        ij ->> user: Do you accept new jars installed?
+        user -->> ij: [Accept/reject]
+        
+        alt Accepted
+            ij ->> ij: Install jars
+        end
+    end
+
+    ij ->> engine: Start process
+    activate engine
+    ij ->> engine: Setup ut context
+    
+    loop For all files
+        ij ->> engine: Generate UtExecutions
+        loop for all UtExecutions for method found by engine
+            engine ->> concrete: Run concretely            
+        end
+        engine --> engine: Minimize all tests for method
+        engine --> engine: Summaries for method
+    end
+    ij ->> engine: Render code
+    engine ->> ij: File with tests
+    deactivate engine
+
+    
+```
+
+# Clients
+
+### Intellij plugin
+> Module: [utbot-intellij](https://github.com/UnitTestBot/UTBotJava/tree/main/utbot-intellij)
+>
+> Purpose: UI interface for Java/Kotlin users
+
+
+TODO (Vassily Kudryashov)
+
+### Maven/gradle plugin
+
+TODO (Nikita Stroganov)
+
+### Github action
+
+TODO (Nikita Stroganov)
+
+### CLI
+
+TODO (Nikita Stroganov)
+
+### Contest estimator
+
+TODO (Rustam Sadykov)
+
+
+# Components
+
+### Symbolic engine
+TODO (Alexey Menshutin)
+
+### Concrete executor
+TODO (Sergey Pospelov)
+
+### Instrumented process
+TODO (Rustam Sadykov)
+
+### Code renderer
+TODO (Egor Kulikov)
+
+### Fuzzer
+TODO (Maxim Pelevin)
+
+### Minimizer
+TODO (Sergey Pospelov)
+
+### Summaries
+TODO (Alexey Zinoviev)
+
+### Sarif report
+TODO (Nikita Stroganov)
+
+
+
+# Cross-cutting subsystems
+
+### Logging
+TODO (Arteniy Kononov)
+
+### RD
+TODO (Arteniy Kononov)
+
+### UTSettings
+TODO (Vassily Kudryashov)
+