Cobrazz improvements

[yoori]

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Improvements:

1. added function RunEmbedded for run components and stop outside without signal ... (author @anton3332), now stop by mutex.unlock
2. added ability to build shared libraries variant (for use in rpm build)
3. ability to build with gdb debug info (USERVER_GEN_GDB_DEBUGINFO - disabled by default) - this allow to see more informative stacks on linux with using debugsource package.
4. added cmake install of project (for use in rpm build or conan build)
5. added environment for build rpm on epel8 linux's (script, scripts for build dep fresh packages and spec file)

Fixes:

1. fix of building inside folder sym linked to other place - in this case "protoc" require that include base is prefix of proto file, for fix - we resolve paths to real paths before protoc execute

Specific changes:

1. we decreased protobuf, grpcio python package dependency versions (requirements*.txt) for use standard python packages installed through rpm's. Otherwise we have strange requirement: should be installed latest version of these packages by pip, independent on versions of c++ packages

All these changes we tested : we link userver preinstalled on host as rpm package, and runned http, grpc components in production

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