The `make install` script, which most users would run via `sudo` to install into `/usr/local`, will use the current umask of the root user when creating certain files and directories. If one uses a restrictive umask by default (e.g. `umask 077`), this means that only the root user will be able to use the full Bitcoin package.

**Expected behavior**

The install script creates all directories and files, including man pages, etc., with permissions `644` / `755`.

**Actual behavior**

Certain folders are created using the default umask, e.g.:

- /usr/local/share/man/man1/
- /usr/local/lib/pkgconfig/
- [...]

This means that only root can access files in these folders and other users won't be able to read the man pages (for example).

**To reproduce**

```bash
$ ./autogen.sh
$ make
$ sudo -iu root
% umask 077
% make install
```

**System information**

OS: Linux
bitcoind version: HEAD
{
    {
        LOCK(cs_args);
        m_settings.ro_config.clear();
        m_config_sections.clear();
    }
    const fs::path conf_path = GetPathArg("-conf", BITCOIN_CONF_FILENAME);
    std::ifstream stream{GetConfigFile(conf_path)};
    
    if (IsArgSet("-conf") && !stream.good()) {
        error = strprintf("specified config file \"%s\" could not be opened.", fs::PathToString(conf_path));
        return false;
    }
    
    if (stream.good()) {
        if (!ReadConfigStream(stream, fs::PathToString(conf_path), error, ignore_invalid_keys)) {
            return false;
        }
        
        
        bool use_conf_file{true};
        {
            LOCK(cs_args);
            if (auto* includes = util::FindKey(m_settings.command_line_options, "includeconf")) {